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Abstract:

The present invention relates to a wireless communication system
supporting carrier aggregation (CA). The present invention provides a
method for allowing a terminal to transmit control information to a base
station in a wireless communication system, and the method comprises
receiving from said base station at least one physical downlink control
channel (PDCCH) and one physical downlink shared channel (PDSCH) through
at least one serving cell that is configured in said terminal; and
transmitting to said base station first control information which has
bundled at least a portion of the control information for said PDCCH
reception or the PDSCH reception that is indicated by said PDCCHs,
wherein said first control information is transmitted using a physical
uplink control channel (PUCCH) resource corresponding to a second control
information, and said second control information can be related to a
PDCCH which was last detected by said terminal among said received
PDCCHs.

Claims:

1. A method of transmitting control information from a terminal to a base
station in a wireless communication system supporting a plurality of
serving cells, the method comprising: receiving at least one of physical
downlink control channel (PDCCH) and physical downlink shared channel
(PDSCH) through at least one serving cell configured in the terminal from
the base station; and transmitting, to the base station, first control
information resulting from performing a bundling on at least a portion of
control information on reception of PDCCH or reception of PDSCH indicated
by the PDCCH, wherein the first control information is transmitted using
physical uplink control channel (PUCCH) resource corresponding to second
control information according to a predetermined rule, and wherein the
second control information is associated with a PDCCH last detected by
the terminal among the received PDCCH.

2. The method according to claim 1, wherein the first control information
is acknowledgement (ACK) or negative acknowledgement (NACK) information,
and the second control information is downlink assignment index (DAI)
information last detected by the terminal from at least one DAI
information transmitted through the PDCCH, and wherein the at least one
DAI information indicates an assignment order of at least one of the
received PDCCH and the received PDSCH.

3. The method according to claim 1, wherein if the PDCCH last detected by
the terminal is included in a primary cell (PCell) of the at least one
serving cell, PUCCH resource corresponding to the second control
information is determined using at least one control channel element
(CCE) index configuring the PDCCH last detected by the terminal.

4. The method according to claim 3, wherein, if the PDCCH last detected
by the terminal is included in a secondary cell (SCell) of the at least
one serving cell, the PUCCH resource corresponding to the second control
information is determined using assignment resource indicator (ARI)
information received from the base station.

5. The method according to claim 4, wherein the ARI information includes
PUCCH resource information corresponding to the second control
information, parameter information for determining the PUCCH resource
corresponding to the second control information, or offset information of
the parameter.

6. The method according to claim 3, wherein if the PDCCH last detected by
the terminal is included in a secondary cell (SCell) of the at least one
serving cell, the PUCCH resource corresponding to the second control
information is configured by the base station in advance through RRC
signaling.

7. The method according to claim 1, wherein information about the PUCCH
resource corresponding to the second control information is configured by
the base station in advance through RRC signaling.

8. The method according to claim 1, wherein the bundling is full
bundling.

9. The method according to claim 1, wherein: the PDCCH carries one or
more transport blocks or indicates a PDSCH carrying one or more transport
blocks, and the first control information and the second control
information include information about one or more transport blocks
included in the PDCCH or the PDSCH indicated by the PDCCH.

10. The method according to claim 9, wherein the first control
information includes information about a maximum number of transport
blocks carried by the PDCCH or the PDSCH indicated by the PDCCH, and if
the number of transport blocks carried by the PDCCH or the PDSCH
indicated by the PDCCH is less than the maximum number of transport
blocks, the first control information of transport blocks excluding the
transport blocks actually carried by the PDCCH or the PDSCH indicated by
the PDCCH among the maximum number of transport blocks carried by the
PDCCH or the PDSCH indicated by the PDCCH is negative acknowledgement
(NACK) information.

11. The method according to claim 9, wherein the first control
information includes information about a maximum number of transport
blocks carried by the PDCCH or the PDSCH indicated by the PDCCH, and if
the number of transport blocks carried by the PDCCH or the PDSCH
indicated by the PDCCH is less than the maximum number of transport
blocks, the first control information of transport blocks excluding the
transport blocks actually carried by the PDCCH or the PDSCH indicated by
the PDCCH among the maximum number of transport blocks carried by the
PDCCH or the PDSCH indicated by the PDCCH is equal to the first control
information of the actually carried transport blocks.

12. A method of, at a base station, receiving control information from a
terminal in a wireless communication system supporting a plurality of
serving cells, the method comprising: transmitting, to the terminal, at
least one of physical downlink control channel (PDCCH) and physical
downlink shared channel (PDSCH) through at least one serving cell
configured in the terminal; and receiving first control information
resulting from performing a bundling on at least a portion of control
information on transmission of PDCCH or transmission of PDSCH indicated
by the PDCCH, wherein the first control information is received using
physical uplink control channel (PUCCH) resource corresponding to second
control information according to a predetermined rule, and wherein the
second control information is associated with a PDCCH last detected by
the terminal among the received PDCCH.

13. The method according to claim 12, wherein the first control
information is acknowledgement (ACK) or negative acknowledgement (NACK)
information, and the second control information is downlink assignment
index (DAI) information last detected by the terminal from at least one
of DAI information transmitted through the PDCCH, and wherein the at
least one DAI information indicates an assignment order of at least one
of the received PDCCH and the received PDSCH.

14. A terminal for transmitting control information to a base station in
a wireless communication system supporting a plurality of serving cells,
the terminal comprising: a receiver for receiving at least one of
physical downlink control channel (PDCCH) and physical downlink shared
channel (PDSCH) through at least one serving cell configured in the
terminal from the base station; a transmitter for transmitting, to the
base station, first control information resulting from performing a
bundling on at least a portion of control information on reception of
PDCCH or reception of PDSCH indicated by the PDCCH; and a processor for
controlling transmission of the first control information to the base
station using physical uplink control channel (PUCCH) resource
corresponding to second control information according to a predetermined
rule, wherein the second control information is associated with a PDCCH
last detected by the terminal among the received PDCCH.

15. The terminal according to claim 14, wherein the first control
information is acknowledgement (ACK) or negative acknowledgement (NACK)
information, and the second control information is downlink assignment
index (DAI) information last detected by the terminal from at least one
DAI information transmitted through the PDCCH, and wherein the at least
one DAI information indicates an assignment order of at least one of the
received PDCCH and the received PDSCH.

16. The terminal according to claim 14, wherein if the PDCCH last
detected by the terminal is included in a primary cell (PCell) of the at
least one serving cell, PUCCH resource corresponding to the second
control information is determined using at least one control channel
element (CCE) index configuring the PDCCH last detected by the terminal.

17. The terminal according to claim 16, wherein, if the PDCCH last
detected by the terminal is included in a secondary cell (SCell) of the
at least one serving cell, the PUCCH resource corresponding to the second
control information is determined using assignment resource indicator
(ARI) information received from the base station.

18. The terminal according to claim 16, wherein if the PDCCH last
detected by the terminal is included in a secondary cell (SCell) of the
at least one serving cell, the PUCCH resource corresponding to the second
control information is configured by the base station in advance through
RRC signaling.

19. The terminal according to claim 14, wherein information about the
PUCCH resources corresponding to the second control information is
configured by the base station in advance through RRC signaling.

20. A base station for receiving control information from a terminal in a
wireless communication system supporting a plurality of serving cells,
the base station comprising: a transmitter for transmitting, to the
terminal, at least one of physical downlink control channel (PDCCH) and
physical downlink shared channel (PDSCH) through at least one serving
cell configured in the terminal; a receiver for receiving first control
information resulting from performing a bundling on at least a portion of
control information on reception of PDCCH or reception of PDSCH indicated
by the PDCCH; and a processor for controlling transmission of the first
control information to the base station using physical uplink control
channel (PUCCH) resource corresponding to second control information
according to a predetermined rule, wherein the second control information
is associated with a PDCCH last detected by the terminal among the
received PDCCH.

Description:

TECHNICAL FIELD

[0001] The present invention relates to a wireless communication system,
and more particularly, to a method and device for transmitting control
information. The wireless communication system may support carrier
aggregation (CA).

BACKGROUND ART

[0002] Wireless communication systems have been diversified in order to
provide various types of communication services such as voice or data
service. In general, a wireless communication system is a multiple access
system capable of sharing available system resources (bandwidth, transmit
power or the like) so as to support communication with multiple users.
Examples of the multiple access system include a Code Division Multiple
Access (CDMA) system, a Frequency Division Multiple Access (FDMA) system,
a Time Division Multiple Access (TDMA) system, an Orthogonal Frequency
Division Multiple Access (OFDMA) system, a Single Carrier Frequency
Division Multiple Access (SC-FDMA) system and the like.

DISCLOSURE

Technical Problem

[0003] An object of the present invention is to provide a method and
device for efficiently transmitting control information in a wireless
communication system. Another object of the present invention is to
provide a channel format for efficiently transmitting control
information, signal processing and a device therefor. Another object of
the present invention is to provide a method and device for efficiently
assigning resources for transmitting control information.

[0004] The technical problems solved by the present invention are not
limited to the above technical problems and other technical problems
which are not described herein will become apparent to those skilled in
the art from the following description.

Technical Solution

[0005] The object of the present invention can be achieved by providing a
method of transmitting control information from a terminal to a base
station in a wireless communication system supporting a plurality of
serving cells, including receiving at least one of physical downlink
control channel (PDCCH) and physical downlink shared channel (PDSCH)
through at least one serving cell configured in the terminal from the
base station, and transmitting, to the base station, first control
information resulting from performing a bundling on at least a portion of
control information on reception of PDCCH or reception of PDSCH reception
indicated by the PDCCH, wherein the first control information is
transmitted using physical uplink control channel (PUCCH) resources
corresponding to second control information according to a predetermined
rule, and wherein the second control information is associated with a
PDCCH last detected by the terminal among the received PDCCHs.

[0006] The first control information may be acknowledgement (ACK) or
negative acknowledgement (NACK) information and the second control
information may be downlink assignment index (DAI) information last
detected by the terminal from at least one DAI information transmitted
through the PDCCH, and the at least one DAI information may indicate an
assignment order of at least one of the received PDCCH and the received
PDSCH.

[0007] If the PDCCH last detected by the terminal is included in a primary
cell (PCell) of the at least one serving cell, PUCCH resource
corresponding to the second control information may be determined using
at least one control channel element (CCE) index configuring the PDCCH
last detected by the terminal.

[0008] If the PDCCH last detected by the terminal is included in a
secondary cell (SCell) of the at least one serving cell, the PUCCH
resource corresponding to the second control information may be
determined using assignment resource indicator (ARI) information received
from the base station.

[0009] The ARI information may include PUCCH resource information
corresponding to the second control information, parameter information
for determining the PUCCH resource corresponding to the second control
information, or offset information of the parameter.

[0010] If the PDCCH last detected by the terminal is included in a
secondary cell (SCell) of the at least one serving cell, the PUCCH
resource corresponding to the second control information may be
configured by the base station in advance through RRC signaling.

[0011] Information about the PUCCH resource corresponding to the second
control information may be configured by the base station in advance
through RRC signaling.

[0012] The bundling may be full bundling.

[0013] The PDCCH may carry one or more transport blocks or indicate a
PDSCH carrying one or more transport blocks, and the first control
information and the second control information may include information
about one or more transport blocks included in the PDCCH or the PDSCH
indicated by the PDCCH.

[0014] The first control information may include information about a
maximum number of transport blocks carried by the PDCCH or the PDSCH
indicated by the PDCCH, and, if the number of transport blocks carried by
the PDCCH or the PDSCH indicated by the PDCCH is less than the maximum
number of transport blocks, the first control information of transport
blocks excluding the transport blocks actually carried by the PDCCH or
the PDSCH indicated by the PDCCH among the maximum number of transport
blocks carried by the PDCCH or the PDSCH indicated by the PDCCH may be
negative acknowledgement (NACK) information.

[0015] The first control information may include information about a
maximum number of transport blocks carried by the PDCCH or the PDSCH
indicated by the PDCCH, and, if the number of transport blocks carried by
the PDCCH or the PDSCH indicated by the PDCCH is less than the maximum
number of transport blocks, the first control information of transport
blocks excluding the transport blocks actually carried by the PDCCH or
the PDSCH indicated by the PDCCH among the maximum number of transport
blocks carried by the PDCCH or the PDSCH indicated by the PDCCH may be
equal to the first control information of the actually carried transport
blocks.

[0016] In another aspect of the present invention, there is provided a
method of, at a base station, receiving control information from a
terminal in a wireless communication system supporting a plurality of
serving cells, including transmitting, to the terminal, at least one of
physical downlink control channel (PDCCH) and physical downlink shared
channel (PDSCH) through at least one serving cell configured in the
terminal, and receiving first control information resulting from
performing a bundling on at least a portion of control information on
transmission of PDCCH or transmission of PDSCH indicated by the PDCCH,
wherein the first control information is received using physical uplink
control channel (PUCCH) resource corresponding to second control
information according to a predetermined rule, and wherein the second
control information is associated with a PDCCH last detected by the
terminal among the received PDCCH.

[0017] The first control information may be acknowledgement (ACK) or
negative acknowledgement (NACK) information, and the second control
information may be downlink assignment index (DAI) information last
detected by the terminal from at least one DAI information transmitted
through the PDCCH, and the at least one DAI information may indicate an
assignment order of at least one of the received PDCCH and the received
PDSCH.

[0018] In another aspect of the present invention, there is provided a
terminal for transmitting control information to a base station in a
wireless communication system supporting a plurality of serving cells,
including a receiver for receiving at least one of physical downlink
control channel (PDCCH) and physical downlink shared channel (PDSCH)
through at least one serving cell configured in the terminal from the
base station, a transmitter for transmitting, to the base station, first
control information resulting from performing a bundling on at least a
portion of control information on reception of PDCCH or reception of
PDSCH indicated by the PDCCH, and a processor for controlling
transmission of the first control information to the base station using
physical uplink control channel (PUCCH) resource corresponding to second
control information according to a predetermined rule, wherein the second
control information is associated with a PDCCH last detected by the
terminal among the received PDCCH.

[0019] The first control information may be acknowledgement (ACK) or
negative acknowledgement (NACK) information, and the second control
information may be downlink assignment index (DAI) information last
detected by the terminal from at least one DAI information transmitted
through the PDCCH, and the at least one DAI information may indicate an
assignment order of at least one of the received PDCCH and the received
PDSCH.

[0020] If the PDCCH last detected by the terminal is included in a primary
cell (PCell) of the at least one serving cell, PUCCH resource
corresponding to the second control information may be determined using
at least one control channel element (CCE) index configuring the PDCCH
which detected by the terminal.

[0021] If the PDCCH last detected by the terminal is included in a
secondary cell (SCell) of the at least one serving cell, the PUCCH
resource corresponding to the second control information may be
determined using assignment resource indicator (ARI) information received
from the base station.

[0022] If the PDCCH last detected by the terminal is included in a
secondary cell (SCell) of the at least one serving cell, the PUCCH
resource corresponding to the second control information may be
configured by the base station in advance through RRC signaling.

[0023] Information about the PUCCH resource corresponding to the second
control information may be configured by the base station in advance
through RRC signaling.

[0024] In another aspect of the present invention, there is provided a
base station for receiving control information from a terminal in a
wireless communication system supporting a plurality of serving cells,
including a transmitter for transmitting, to the terminal, at least one
of physical downlink control channel (PDCCH) and physical downlink shared
channel (PDSCH) through at least one serving cell configured in the
terminal, a receiver for receiving first control information resulting
from performing a bundling on at least a portion of control information
on reception of PDCCH or reception of PDSCH indicated by the PDCCH, and a
processor for controlling transmission of the first control information
to the base station using physical uplink control channel (PUCCH)
resource corresponding to second control information according to a
predetermined rule, wherein the second control information is associated
with a PDCCH last detected by the terminal among the received PDCCH.

Advantageous Effects

[0025] According to the present invention, it is possible to efficiently
transmit control information in a wireless communication system. It is
possible to provide a channel format for efficiently transmitting control
information, signal processing and a device therefor. It is possible to
efficiently assign resources for transmitting control information.

[0026] The effects of the present invention are not limited to the
above-described effects and other effects which are not described herein
will become apparent to those skilled in the art from the following
description.

DESCRIPTION OF DRAWINGS

[0027] FIG. 1 is a diagram showing the configuration of a user equipment
(UE) and a base station to which the present invention is applied;

[0028] FIG. 2 is a diagram showing a signal processing procedure of
transmitting an uplink signal at a UE;

[0029]FIG. 3 is a diagram showing a signal processing procedure of
transmitting a downlink signal at a base station;

[0030] FIG. 4 is a diagram showing an SC-FDMA scheme and an OFDMA scheme
to which the present invention is applied;

[0031]FIG. 5 is a diagram showing examples of mapping input symbols to
subcarriers in a frequency domain while satisfying a single carrier
property;

[0032] FIG. 6 is a diagram showing a signal processing procedure of
mapping DFT process output samples to a single carrier in clustered
SC-FDMA;

[0042] FIG. 18 is a diagram showing channelization of a mixed structure of
PUCCH format 1/1a/1b and format 2/2a/2b within the same PRB;

[0043]FIG. 19 is a diagram showing assignment of a physical resource
block (PRB);

[0044] FIG. 20 is a diagram showing a concept for managing downlink
component carriers (DL CCs) at a base station;

[0045] FIG. 21 is a diagram showing a concept for managing uplink
component carriers (UL CCs) at a UE;

[0046]FIG. 22 is a diagram showing a concept in which one media access
control (MAC) layer manages multiple carriers at a base station;

[0047]FIG. 23 is a diagram showing a concept in which one MAC layer
manages multiple carriers at a UE;

[0048]FIG. 24 is a diagram showing a concept in which a plurality of MAC
layers manages multiple carriers at a base station;

[0049]FIG. 25 is a diagram showing a concept in which a plurality of MAC
layers manages multiple carriers at a UE;

[0050] FIG. 26 is a diagram showing another concept in which a plurality
of MAC layers manages multiple carriers at a base station;

[0051]FIG. 27 is a diagram showing another concept in which a plurality
of MAC layers manages multiple carriers at a UE;

[0052]FIG. 28 is a diagram showing asynchronous carrier aggregation (CA)
in which five downlink component carriers (DL CCs) are linked with one
uplink CC (UL CC);

[0053] FIGS. 29 to 32 are diagrams illustrating a structure of PUCCH
format 3 according to the present invention and a signal processing
procedure therefor;

[0054]FIG. 33 is a diagram illustrating resource assignment indicated to
a UE according to an embodiment of the present invention;

[0055]FIG. 34 is a diagram showing ACK/NACK transmission resources
according to an embodiment of the present invention;

[0056] FIG. 35 is a diagram showing ACK/NACK transmission if a UE does not
receive one of a plurality of PDCCHs in a TDD system according to an
embodiment of the present invention;

[0057]FIG. 36 is a diagram illustrating a method of indicating a total
number of PDCCHs according to an embodiment of the present invention;

[0058] FIG. 37 is a diagram illustrating a method of indicating a PDCCH
order value according to an embodiment of the present invention;

[0059]FIG. 38 is a diagram illustrating a full bundling method according
to an embodiment of the present invention;

[0060] FIG. 39 is a diagram illustrating a partial bundling method
according to an embodiment of the present invention;

[0061]FIG. 40 is a diagram showing an example of transmitting bundled
ACK/NACK information via PUCCH resources determined via a last detected
DAI value according to an embodiment of the present invention;

[0062]FIG. 41 is a diagram showing an example of using general DAI
information and modified DAI information according to an embodiment of
the present invention;

[0063] FIG. 42 is a diagram showing an example of using general DAI
information and modified DAI information according to another embodiment
of the present invention; and

[0064]FIG. 43 is a diagram showing an example of using general DAI
information and modified DAI information according to another embodiment
of the present invention.

BEST MODE

[0065] Reference will now be made in detail to the preferred embodiments
of the present invention, examples of which are illustrated in the
accompanying drawings. The detailed description set forth below in
connection with the appended drawings is intended as a description of
exemplary embodiments and is not intended to represent the only
embodiments in which the concepts explained in these embodiments can be
practiced. The detailed description includes details for the purpose of
providing an understanding of the present invention. However, it will be
apparent to those skilled in the art that these teachings may be
implemented and practiced without these specific details.

[0066] The following technique, device, and system can be applied to a
variety of radio multiple access systems. The radio multiple access
system may include, for example, CDMA (Code Division Multiple Access),
FDMA (Frequency Division Multiple Access), TDMA (Time Division Multiple
Access), OFDMA (Orthogonal Frequency Division Multiple Access), SC-FDMA
(Single Carrier Frequency Division Multiple Access), multi carrier
frequency division multiple access (MC-FDMA) system and the like. CDMA
may be embodied as wireless (or radio) technology such as UTRA (Universal
Terrestrial Radio Access) or CDMA2000. TDMA may be embodied with wireless
(or radio) technology such as GSM (Global System for Mobile
communications)/GPRS (General Packet Radio Service)/EDGE (Enhanced Data
Rates for GSM Evolution). OFDMA may be embodied with wireless (or radio)
technology such as Institute of Electrical and Electronics Engineers
(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA
(Evolved UTRA). UTRAN is a part of the UMTS (Universal Mobile
Telecommunications System). 3GPP (3rd Generation Partnership Project) LTE
(long term evolution) is a part of the E-UMTS (Evolved UMTS), which uses
E-UTRA. 3GPP LTE employs OFDMA in downlink and employs SC-FDMA in uplink.
LTE-Advanced (LTE-A) is an evolved version of 3GPP LTE. For convenience
of description, assume that the present invention is applicable to 3GPP
LTE/LTE-A. However, the technical features of the present invention are
not limited thereto. For instance, although the following detailed
description is given on the assumption that 3GPP LTE/LTE-A mobile
communication system is used, it is applicable to other prescribed mobile
communication systems by excluding unique items of 3GPP LTE.

[0067] In some instances, well-known structures and devices are omitted in
order to avoid obscuring the concepts of the present invention and the
important functions of the structures and devices are shown in block
diagram form. The same reference numbers will be used throughout the
drawings to refer to the same or like parts.

[0068] In the present invention, it is assumed that a terminal is a fixed
or mobile terminal and includes devices which communicate with a base
station to transmit and receive a variety of data and control
information. The terminal may be referred to as the term user equipment
(UE), mobile station (MS), mobile terminal (MT), user terminal (UT),
subscribe station (SS), wireless device, personal digital assistant
(PDA), wireless modem, handheld device, etc.

[0069] A base station means a fixed station communicating with a terminal
or another base station and communicates with a terminal and another base
station to exchange a variety of data and control information. The base
station may be referred to as an evolved NodeB (eNB), base transceiver
system (BTS), access point, etc.

[0070] In the present invention, assigning a specific signal to a
frame/subframe/slot/carrier/subcarrier means transmitting the specific
signal through the carrier/subcarrier during a period or timing of the
frame/subframe/slot.

[0071] In the present invention, rank or transmission rank means the
number of layers multiplexed or assigned on one OFDM symbol or one
resource element.

[0074] In particular, a resource element (RE) assigned to or belonging to
a PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH may be referred to as a
PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH RE or
PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH resource.

[0075] Accordingly, transmission of a PUCCH/PUSCH/PRACH by a terminal may
have the same meaning as transmission of uplink control
information/uplink data/random access signal on a PUCCH/PUSCH/PRACH.
Transmission of a PDCCH/PCFICH/PHICH/PDSCH by a base station may have the
same meaning as transmission of downlink control information/downlink
data on a PDCCH/PCFICH/PHICH/PD SCH.

[0076] Mapping ACK/NACK information to a specific constellation point may
have the same meaning as mapping ACK/NACK information to a specific
complex modulation symbol. In addition, mapping ACK/NACK information to a
specific complex modulation symbol may have the same meaning as
modulating ACK/NACK information into a specific complex modulation symbol

[0077] FIG. 1 shows the configuration of a user equipment (UE) and a base
station (BS) to which the present invention is applied. The UE operates
as a transmission apparatus in uplink and operates as a reception
apparatus in downlink. In contrast, a base station operates as a
reception apparatus in uplink and operates as a transmission apparatus in
downlink.

[0078] Referring to FIG. 1, the UE and the BS include antennas 500a and
500b for receiving information, data, signals and/or messages,
transmitters 100a and 100b for transmitting information, data, signals,
and/or messages by controlling the antennas 500a and 500b, receivers 300a
and 300b for receiving information, data, signals and/or messages by
controlling the antennas 500a and 500b, and memories 200a and 200b for
temporarily or permanently storing a variety of information in the
wireless communication system. The UE and the BS further include
processors 400a and 400b which are operatively connected to components of
the transmitters, the receivers and the memories to control the
components, respectively.

[0079] The transmitter 100a, the memory 200a, the receiver 300a, and the
processor 400a in the UE may be configured as independent components by
separate chips or their separate chips may be incorporated into a single
chip. Likewise, the transmitter 100b, the memory 200b, the receiver 300b,
and the processor 400b in the BS may be configured as independent
components on separate chips or their separate chips may be incorporated
into a single chip. The transmitter and the receiver may be configured as
a single transceiver in the UE or the BS.

[0080] The antennas 500a and 500b transmit signals generated from the
transmitters 100a and 100b to an external device, or transfer radio
signals received from an external device to the receivers 300a and 300b.
The antennas 500a and 500b can be referred as antenna ports. Each antenna
port can correspond to one physical antenna or can be configured by a
combination of more than one physical antenna. If the transmitter and the
receiver support a Multiple Input Multiple Output (MIMO) function using a
plurality of antennas, the transmitter and the receiver may be connected
to two or more antennas.

[0081] The processors 400a and 400b generally provide overall control to
the components or modules of the UE and the BS. Especially, the
processors 400a and 400b may carry out a control function for performing
the present invention, a Media Access Control (MAC) frame variable
control function based on service characteristics and a propagation
environment, a power saving mode function for controlling idle-mode
operations, a handover function, and an authentication and encryption
function. The processors 400a and 400b may also be referred to as
controllers, microcontrollers, microprocessors, microcomputers, etc. The
processors 400a and 400b may be achieved by hardware, firmware, software,
or a combination thereof.

[0082] The processor 400a of the UE transmits first control information
which has bundled at least a portion of control information for reception
of at least one PDCCH and second control information to the BS through
the transmitter.

[0083] In addition, the processor 400a selects physical uplink control
channel (PUCCH) resources for the first control information and the
second control information from a plurality of PUCCH resources and
transmits a PUCCH signal carrying a modulation value corresponding to the
first control information and the second information to the BS through
the transmitter using the selected PUCCH resources. At this time, the
first control information and the second control information may be
identified by a combination of the selected PUCCH resources and the
modulation value.

[0084] In addition, the processor 400a controls the selected PUCCH
resources to be used as preset first PUCCH resources of the plurality of
PUCCH resources if the first control information is NACK information and
controls the selected PUCCH resources to be used as PUCCH resources
excluding the first PUCCH resources of the plurality of PUCCH resources
if the first control information is ACK information.

[0085] The processor 400a may control the first control information and
the second control information to become information about a PDCCH before
generating discontinuous transmission (DTX) information of the received
at least one PDCCH if control information for reception of at least one
PDCCH includes DTX information. At this time, if the first control
information is ACK, the processor 400a may control transmission of the
first control information and the second control information to the BS.

[0087] If the present invention is implemented using firmware or software,
firmware or software may be configured to include a module, a procedure,
a function, etc. for performing functions or operations of the present
invention. This firmware or software configured to implement the present
invention may be provided in the processors 400a and 400b, or may be
stored in the memories 200a and 200b and driven by the processors 400a
and 400b.

[0088] The transmitters 100a and 100b are scheduled by the processors 400a
and 400b or schedulers connected to the processors to perform
predetermined coding and modulation with respect to a signal or data to
be transmitted to an external device and to send the signal or data to
the antennas 500a and 500b. The transmitters 100a and 100b and the
receivers 300a and 300b of the UE and the BS may be differently
configured according to a procedure of processing a transmitted signal or
a received signal.

[0089] The memories 200a and 200b may store a program for processing and
controlling the processors 400a and 400b and temporarily store
input/output information. In addition, the memories 200a and 200b may be
used as buffers. The memories may include at least one of a flash memory
type, hard disk type, multimedia card micro type, or card type memory
(e.g., a SD or XD memory), a Random Access Memory (RAM), a Static Random
Access Memory (SRAM), a Read-Only Memory (ROM), an Electrically Erasable
Programmable Read-Only Memory (EEPROM), a Programmable Read-Only Memory
(PROM), a magnetic memory, a magnetic disk, or an optical disk.

[0090] FIG. 2 is a diagram showing a signal processing procedure of
transmitting an uplink signal at a UE. Referring to FIG. 2, a transmitter
100a of the UE includes a scrambling module 201, a modulation mapper 202,
a precoder 203, a resource element mapper 204 and an SC-FDMA signal
generator 205.

[0091] In order to transmit an uplink signal, the scrambling module 201
may scramble a transmitted signal using a scramble signal. The scrambled
signal is input to the modulation mapper 202 and is modulated into a
complex modulation symbol using a binary phase shift keying (BPSK),
quadrature phase shift keying (QPSK) or 16 quadrature amplitude
modulation (QAM)/64QAM modulation scheme according to the kind of the
transmitted signal or the channel state. The modulated complex modulation
symbol is processed by the precoder 203 and is input to the resource
element mapper 204. The resource element mapper 204 may map the complex
modulation symbol to time-frequency resource elements. The processed
signal may be transmitted to the BS through the SC-FDMA signal generator
205 and antenna ports.

[0092]FIG. 3 is a diagram showing a signal processing procedure of
transmitting a downlink signal at a BS. Referring to FIG. 3, the
transmitter 100b of the BS may include a scrambling module 301, a
modulation mapper 302, a layer mapper 303, a precoder 304, a resource
element mapper 305 and an OFDMA signal generator 306.

[0093] In order to transmit a signal or at least one codeword in downlink,
similarly to FIG. 2, the signal or the codeword may be modulated into a
complex modulation symbol through the scrambling module 301 and the
modulation mapper 302. The complex modulation symbol is mapped to a
plurality of layers by the layer mapper 303 and each layer may be
multiplied by a precoding matrix using the precoder 304 and may be
assigned to each transmit antenna. The processed signals which will
respectively be transmitted via antennas may be mapped to time-frequency
resource elements by resource element mappers 305, and may respectively
be transmitted via OFDM signal generators 306 and antennas.

[0094] In a wireless communication system, in a case in which a UE
transmits a signal in uplink, a Peak-to-Average Ratio (PAPR) may be more
problematic than the case in which a BS transmits a signal in downlink.
Accordingly, as described above with reference to FIGS. 2 and 3, an OFDMA
scheme is used to transmit a downlink signal, while an SC-FDMA scheme is
used to transmit an uplink signal.

[0095] FIG. 4 is a diagram showing an SC-FDMA scheme and an OFDMA scheme
to which the present invention is applied. In the 3GPP system, the OFDMA
scheme is used in downlink and the SC-FDMA is used in uplink.

[0096] Referring to FIG. 4, a UE for UL signal transmission and a BS for
DL signal transmission are identical in that a serial-to-parallel
converter 401, a subcarrier mapper 403, an M-point Inverse Discrete
Fourier Transform (IDFT) module 404 and a Cyclic Prefix (CP) adding
module 406 are included. The UE for transmitting a signal using an
SC-FDMA scheme further includes an N-point DFT module 402. The N-point
DFT module 402 partially offsets an IDFT process influence of the M-point
IDFT module 404 such that the transmitted signal has a single carrier
property.

[0097] SC-FDMA must satisfy a single carrier property. FIG. 5 is a diagram
showing examples of mapping input symbols to subcarriers in a frequency
domain while satisfying a single carrier property. According to one of
FIG. 5(a) and FIG. 5(b), if DFT symbols are assigned to subcarriers, a
transmitted signal satisfying a single carrier property may be obtained.
FIG. 5(a) shows a localized mapping scheme and FIG. 5(b) shows a
distributed mapping scheme.

[0098] A clustered DFT-s-OFDM scheme may be employed in the transmitters
100a and 100b. In the clustered SC-FDMA scheme which is a modified form
of the SC-FDMA scheme, a precoded signal is divided into several
subblocks and then is non-contiguously mapped to subcarriers. FIGS. 6 to
8 show examples of mapping input symbols to a single carrier by clustered
DFT-s-OFDM.

[0099] FIG. 6 is a diagram showing a signal processing procedure of
mapping DFT process output samples to a single carrier in clustered
SC-FDMA. FIGS. 7 and 8 are diagrams showing a signal processing procedure
of DFT process output samples to multiple carriers in clustered SC-FDMA.
FIG. 6 shows an example of applying an intra-carrier clustered SC-FDMA
scheme and FIGS. 7 and 8 show examples of applying an inter-carrier
clustered SC-FDMA scheme. FIG. 7 shows the case in which a signal is
generated by a single IFFT block when a subcarrier spacing between
contiguous component carriers is aligned in a state in which component
carriers are contiguously assigned in a frequency domain and FIG. 8 shows
the case in which a signal is generated by a plurality of IFFT blocks in
a state in which component carriers are non-contiguously assigned in a
frequency domain.

[0101] In the segmented SC-FDMA scheme, IFFTs corresponding in number to a
certain number of DFTs are applied such that the DFTs and the IFFTs are
in one-to-one correspondence and DFT spreading of the conventional
SC-FDMA scheme and the frequency subcarrier mapping configuration of the
IFFTs are extended. Therefore, the segmented SC-FDMA scheme also referred
to as an NxSC-FDMA or NxDFT-s-OFDMA scheme. In the present specification,
the generic term "segmented SC-FDMA" is used. Referring to FIG. 9, the
segmented SC-FDMA scheme is characterized in that modulation symbols of
an entire time domain are grouped into N (N being an integer greater than
1) groups and a DFT process is performed on a group unit basis, in order
to reduce a single carrier property condition.

[0102] FIG. 10 is a diagram showing examples of a radio frame structure
used in a wireless communication system. In particular, FIG. 10(a) shows
a radio frame according to a frame structure type 1 (FS-1) of a 3GPP
LTE/LTE-A system and FIG. 10(b) shows a radio frame according to a frame
structure type 2 (FS-2) of a 3GPP LTE/LTE-A system. The frame structure
of FIG. 10(a) is applicable to a frequency division duplex (FDD) mode and
a half FDD (H-FDD) mode. The frame structure of FIG. 10(b) is applicable
to a time division duplex (TDD) mode.

[0103] Referring to FIG. 10, the radio frame used in 3GPP LTE/LTE-A has a
length of 10 ms (307200Ts) and includes 10 subframes having the same
size. The 10 subframes of one radio frame may be numbered. Here, Ts
denotes a sampling time and is expressed by Ts=1/(2048×15
kHz). Each subframe has a length of 1 ms and includes two slots. Within
one radio frame, 20 slots are sequentially numbered 0 to 19. Each slot
has a length of 0.5 ms. A time required to transmit one subframe is
defined as a transmission time interval (TTI). Time resources may be
divided by a radio frame number (or a radio frame index), a subframe
number (or a subframe number) and a slot number (or a slot index).

[0104] The radio frame may be differently configured according to a duplex
mode. For example, since downlink transmission and uplink transmission
are divided according to a frequency in a FDD mode, the radio frame
includes only one of a downlink subframe or an uplink subframe.

[0105] Since downlink transmission and uplink transmission are divided
according to a time in a TDD mode, a subframe of a frame is divided into
a downlink subframe and an uplink subframe.

[0106] FIG. 11 is a diagram showing an uplink subframe structure used in
the present invention. Referring to FIG. 11, an uplink subframe is
divided into a data region and a control region in a frequency domain. At
least one physical uplink control channel (PUCCH) may be assigned to the
control region in order to transmit uplink control information (UCI). In
addition, at least one physical uplink shared channel (PUSCH) may be
assigned to a data region in order to transmit user data. Here, if a UE
employs an SC-FDMA scheme in LTE release 8 or release 9, the PUCCH and
the PUSCH may not be simultaneously transmitted in the same subframe in
order to maintain a single carrier property.

[0107] The size and usage of the UCI transmitted via the PUCCH differ
according to PUCCH format. In addition, the size of the UCI may vary
according to a coding rate. For example, the following PUCCH formats may
be defined.

[0114] Table 1 shows a modulation scheme and the number of bits per
subframe according to a PUCCH format. Table 2 shows the number of
reference signals (RSs) per slot according to a PUCCH format. Table 3
shows SC-FDMA symbol locations of an RS according to a PUCCH format. In
Table 1, the PUCCH formats 2a and 2b correspond to the normal CP case.

[0115] In an uplink subframe, subcarriers distant from a direct current
(DC) subframe are used as a control region. In other words, subcarriers
located at both ends of an uplink transmission bandwidth are assigned to
UCI transmission. The DC subcarrier is a component remaining after signal
transmission and is mapped to a carrier frequency f0 in a frequency
up-conversion process by the OFDMA/SC-FDMA signal generator.

[0116] A PUCCH for one UE is assigned to an RB pair in a subframe and RBs
belonging to the RB pair occupy different subcarriers in two slots. The
assigned PUCCH is expressed by frequency hopping of an RB pair, to which
the PUCCH is assigned, at a slot edge. If frequency hopping is not
applied, the RB pair occupies the same subcarrier in two slots.
Regardless of frequency hopping, since the PUCCH for the UE is assigned
to the RB pair in the subframe, the same PUCCH is transmitted via one RB
in each slot of the subframe once, that is, is transmitted a total of
twice.

[0117] Hereinafter, an RB pair used for PUCCH transmission within a
subframe is referred to as a PUCCH region. In addition, the PUCCH region
and a code used in the region are referred to as PUCCH resource. That is,
different PUCCH resources may have different PUCCH regions or different
codes in the same PUCCH region. For convenience of description, a PUCCH
for transmitting ACK/NACK information is referred to as an ACK/NACK
PUCCH, a PUCCH for transmitting CQI/PMI/RI information is referred to as
channel state information (CSI) PUCCH and a PUCCH for transmitting SR
information is referred to as an SR PUCCH.

[0118] A BS assigns PUCCH resources for uplink control information
transmission to a UE using an explicit method or an implicit method.

[0120] In a wireless communication system, a UE and a BS transmit and
receive a signal or data to and from each other. If the BS transmits data
to the UE, the UE decodes the received data and transmits ACK to the BS
if data decoding is successfully performed. If data decoding is not
successfully performed, the UE transmits NACK to the BS. The same is true
when the UE transmits data to the BS. In a 3GPP LTE system, a UE receives
a PDSCH from a BS and transmits ACK/NACK for the PDSCH to the BS through
an implicit PUCCH determined by a PDCCH carrying scheduling information
of the PDSCH. If the UE does not receive data, the UE may be regarded as
being in a discontinuous transmission (DTX) state and may be regarded as
not receiving data or may be regarded as receiving data but as not
successfully decoding the data (NACK) according to a predetermined rule.

[0121]FIG. 12 is a diagram showing a structure for determining a PUCCH
for ACK/NACK transmission to which the present invention is applied.

[0122] PUCCH resources for ACK/NACK information transmission are not
assigned to UEs in advance but a plurality of PUCCH resources is divided
and used by a plurality of UEs at each point of time. More specifically,
PUCCH resources used to transmit ACK/NACK information by a UE are
determined using an implicit method based on a PDCCH carrying scheduling
information of a PDSCH for transmitting downlink data. An entire region,
in which the PDCCH is transmitted, in a downlink subframe, includes a
plurality of control channel elements (CCEs) and a PDCCH transmitted to
the UE includes one or more CCEs. The CCE includes a plurality (e.g., 9)
of resource element groups (REGs). One REG includes four neighboring
resource elements (REs) in a state of excluding a reference signal (RS).
The UE transmits ACK/NACK information via implicit PUCCH resources
derived or calculated by a function of a specific CCE index (e.g., a
first or lowest CCE index) among CCE indices configuring the received
PDCCH.

[0123] Referring to FIG. 12, the lowest CCE index of the PDCCH corresponds
to a PUCCH resource index for ACK/NACK transmission. As shown in FIG. 12,
if it is assumed that scheduling information of the PDSCH is transmitted
to the UE via a PDCCH including fourth to sixth CCEs, the UE transmits
ACK/NACK to the BS via PUCCH resources corresponding to a fourth PUCCH
derived or calculated from a fourth CCE index which is a lowest CCE
configuring the PDCCH.

[0124]FIG. 12 shows the case in which a maximum of M' CCEs is present in
a downlink subframe and a maximum of M PUCCH resources is present in an
uplink subframe. Although M'=M may be possible, M' and M values may be
different and mapping of CCEs and PUCCH resources may overlap. For
example, a PUCCH resource index may be determined as follows.

n.sup.(1)PUCCH=nCCE+N.sup.(1)PUCCH [Equation 1]

[0125] n.sub.(1)PUCCH denotes a PUCCH resource index for transmitting
ACK/NACK information, and N.sup.(1)PUCCH denotes a signal value
received from a higher layer. nCCE denotes a lowest value among CCE
indices used for PDCCH transmission.

[0127]FIG. 13 shows PUCCH formats 1a and 1b in the normal CP case. FIG.
14 shows PUCCH formats 1a and 1b in the extended CP case. In the PUCCH
formats 1a and 1b, the same uplink control information is repeated within
a subframe in slot units. Each UE transmits an ACK/NACK signal through
different resources including different cyclic shifts (CSs) (frequency
domain codes) of a computer-generated constant amplitude zero auto
correlation (CG-CAZAC) sequence and orthogonal covers (OCs) or orthogonal
cover codes (OCCs) (time domain spreading codes). The OC includes, for
example, a Walsh/DFT orthogonal code. If the number of CSs is 6 and the
number of OCs is 3, a total of 18 UEs may be multiplexed in the same
physical resource block (PRB) based on a single antenna. Orthogonal
sequences w0, w1, w2 and w3 may be applied in an arbitrary time domain
(after FFT modulation) or an arbitrary frequency domain (before FFT
modulation). The slot level structure of PUCCH format 1 for SR
information transmission is equal to that of PUCCH formats 1a and 1b and
only a modulation method thereof is different from that of PUCCH formats
1a and 1b.

[0128] For ACK/NACK for SR information transmission and semi-persistent
scheduling (SPS), PUCCH resources including CSs, OCs, PRBs and RSs may be
assigned to a UE through radio resource control (RRC). As shown in FIG.
12, for dynamic ACK/NACK (or ACK/NACK for non-persistent scheduling)
feedback and ACK/NACK feedback for a PDCCH indicating SPS release, PUCCH
resources may be implicitly assigned to the UE using a lowest CCE index
of a PDCCH for SPS release or a PDCCH corresponding to a PDSCH.

[0129]FIG. 15 shows a PUCCH format 2/2a/2b in the normal CP case. FIG. 16
shows a PUCCH format 2/2a/2b in the extended CP case. Referring to FIGS.
15 and 16, one subframe includes 10 QPSK data symbols in addition to an
RS symbol in the normal CP case. Each QPSK symbol is spread in a
frequency domain by a CS and is then mapped to a corresponding SC-FDMA
symbol. SC-FDMA symbol level CS hopping may be applied in order to
randomize inter-cell interference. RSs may be multiplexed by CDM using a
CS. For example, if it is assumed that the number of available CSs is 12
or 6, 12 or 6 UEs may be multiplexed in the same PRB. For example, in the
PUCCH formats 1/1a/1b and 2/2a/2b, a plurality of UEs may be multiplexed
by CS+OC+PRB and CS+PRB.

[0130] Length-4 and length-3 OCs for PUCCH formats 1/1a/1b are shown in
the following Tables 4 and 5.

[0144] CQI, PMI, RI, and a combination of CQI and ACK/NACK may be
transmitted through PUCCH format 2/2a/2b. Reed Muller (RM) channel coding
may be applied.

[0145] For example, in an LTE system, channel coding for uplink CQI is
described as follows. A bit stream a0, a1, a2, a3, .
. . , aA-1 is channel coded using a (20, A) RM code. Table 7 shows a
base sequence for the (20, A) code. a0 and aA-1 denote a most
significant bit (MSB) and a least significant bit (LSB), respectively. In
the extended CP case, a maximum number of transmitted bits is 11 bits
except for the case in which CQI and ACK/NACK are simultaneously
transmitted. After coding to 20 bits using an RM code, QPSK modulation
may be applied. Before QPSK modulation, coded bits may be scrambled.

[0151]FIG. 19 is a diagram showing assignment of a physical resource
block (PRB). As shown in FIG. 19, the PRB may be used to transmit a PUCCH
at a slot ns.

[0152] A multi-carrier system or a carrier aggregation system refers to a
system which uses an aggregate of a plurality of carriers having a
bandwidth less than a target bandwidth for broadband support. When a
plurality of carriers having a bandwidth less than a target bandwidth is
aggregated, the bandwidth of the aggregated carriers may be restricted to
a bandwidth used in a conventional system for backward compatibility with
the conventional system. For example, the conventional LTE system
supports bandwidths of 1.4, 3, 5, 10, 15 and 20 MHz and an LTE_Advanced
(LTE_A) system evolved from the LTE system may support a bandwidth
greater than 20 MHz using only the bandwidths supported by the LTE
system. Alternatively, regardless of the bandwidths used in the
conventional system, a new bandwidth may be defined so as to support CA.
Multi-carrier may be used interchangeably with carrier aggregation and
bandwidth aggregation. Carrier aggregation may include contiguous carrier
aggregation and non-contiguous carrier aggregation. In addition, carrier
aggregation may include intra-band carrier aggregation and inter-band
carrier aggregation.

[0153] FIG. 20 is a diagram showing the concept for managing downlink
component carriers (DL CCs) at a BS, and FIG. 21 is a diagram showing a
concept for managing uplink component carriers (UL CCs) at a BS. For
convenience of description, assume that a higher layer is a media access
layer (MAC) layer in FIGS. 19 and 20.

[0154]FIG. 22 is a diagram showing a concept in which one media access
control (MAC) layer manages multiple carriers at a BS, and FIG. 23 is a
diagram showing the concept in which one MAC layer manages multiple
carriers at a UE.

[0155] Referring to FIGS. 22 and 23, one MAC layer manages one or more
frequency carriers so as to perform transmission and reception. Since
frequency carriers managed by one MAC layer do not need to be contiguous
to each other, resource management is flexible. In FIGS. 22 and 23, one
physical (PHY) layer means one component carrier, for convenience. One
PHY layer does not necessarily mean an independent radio frequency (RF)
device. In general, one independent RF device means one PHY layer, but
the present invention is not limited thereto. One RF device may include
several PHY layers.

[0156]FIG. 24 is a diagram showing a concept in which a plurality of MAC
layers manages multiple carriers at a BS. FIG. 25 is a diagram showing a
concept in which a plurality of MAC layers manages multiple carriers at a
UE. FIG. 26 is a diagram showing another concept in which a plurality of
MAC layers manages multiple carriers at a BS. FIG. 27 is a diagram
showing another concept in which a plurality of MAC layers manages
multiple carriers at a UE.

[0157] In addition to the structures shown in FIGS. 22 and 23, several MAC
layers may control several carriers as shown in FIGS. 24 to 27.

[0158] For example, each MAC layer may control each carrier in one-to-one
correspondence as shown in FIGS. 24 and 25 or each MAC layer may control
each carrier in one-to-one correspondence with respect to some carriers
and one MAC layer may control one or more carriers with respect to the
remaining carriers as shown in FIGS. 26 and 27.

[0159] The system includes a plurality of carriers such as carrier one to
carriers N and the carriers may be contiguous or non-contiguous,
regardless of uplink/downlink. A TDD system is configured to manage a
plurality (N) of carriers in downlink and uplink transmission. A FDD
system is configured such that a plurality of carriers is used in each of
uplink and downlink. In the case of the FDD system, asymmetric CA in
which the numbers of carriers aggregated in uplink and downlink and/or
the bandwidths of the carriers are different may also be supported.

[0160] When the numbers of aggregated component carriers in uplink and
downlink are the same, it is possible to configure all component carriers
so as to enable backward compatibility with the conventional system.
However, component carriers which do not consider compatibility are not
excluded from the present invention.

[0161]FIG. 28 is a diagram showing asynchronous carrier aggregation (CA)
in which five downlink component carriers (DL CCs) are linked with one
uplink CC (UL CC). The shown asymmetric CA is set from the viewpoint of
UCI transmission. Specific UCI (e.g., ACK/NACK response) for a plurality
of DL CCs is collected at one UL CC and is transmitted. In addition, even
when a plurality of UL CCs is configured, specific UCI (e.g., ACK/NACK
response for DL CC) is transmitted via a predetermined UL CC (e.g., a
primary CC, a primary cell or a PCell). For convenience, if it is assumed
that each DL CC may carry a maximum of two codewords and the number of
ACK/NACK bits for each CC depends on a maximum number of codewords per CC
(e.g., if the maximum number of codewords set from the BS at a specific
CC is 2, even when a specific PDCCH uses only one codeword at a CC, the
number of ACK/NACK bits therefor is 2 which is the maximum number of
codewords at CC), the number of UL ACK/NACK bits is at least two at one
subframe per DL CC. In this case, in order to transmit ACK/NACK for data,
which is received through five DL CCs, through one UL CC, ACK/NACK of at
least 10 bits is necessary for one subframe. In order to distinguish a
DTX state of each DL CC, at least 12 bits (=55=3125=11.61 bits) are
necessary for ACK/NACK transmission. Since ACK/NACK of up to 2 bits may
be transmitted in the existing PUCCH formats 1a/1b, such a structure
cannot transmit extended ACK/NACK information. For convenience, although
an example in which the amount of UCI is increased due to CA is
described, the amount of UCI may be increased due to increase in the
number of antennas, presence of a backhaul subframe in a TDD system and a
relay system, etc. Similarly to ACK/NACK, even when control information
associated with a plurality of DL CCs is transmitted through one UL CC,
the amount of control information to be transmitted is increased. For
example, in the case in which CQI/PMI/RI for a plurality of DL CCs must
be transmitted, UCI payload may be increased. Meanwhile, although
ACK/NACK information for codewords are described in the present
invention, transport blocks corresponding to the codewords may be present
and ACK/NACK information for the transport blocks may be applied. In
addition, although ACK/NACK information for one DL subframe per DL CC for
transmission of one UL CC is shown, ACK/NACK information for one or more
DL subframes per DL CC for transmission of one UL CC may be applied in a
TDD system.

[0162] A UL anchor CC (UL primary CC (PCC)) shown in FIG. 28 is used to
transmit PUCCH resources or UCI and may be determined in a cell-specific
or UE-specific manner. For example, the UE may determine a CC which
attempts initial random access as a primary CC. At this time, a DTX state
may be explicitly fed back and the same state as NACK may be fed back to
be shared.

[0163] The LTE-A system uses the concept of a cell in order to manage
radio resources. A cell is defined as a combination of downlink resources
and uplink resources, and the uplink resources are not mandatory.
Accordingly, the cell may be composed of downlink resources alone or both
downlink resources and uplink resources. Linkage between a downlink
resource carrier frequency (or a DL CC) and a uplink resource carrier
frequency (or a UL CC) per cell may be indicated by a system information
block (SIB). A cell operating on a primary frequency resource (e.g., PCC)
is referred to as a primary cell (PCell) and a cell operating on a
secondary frequency resource (e.g., a SCC) is referred to as a secondary
cell (SCell). The PCell may indicate a cell used when a UE performs an
initial connection establishment process or a connection re-establishment
process). The PCell may indicate a cell indicated in a handover process.
In LTE-A release 10, only one PCell may be present upon carrier
aggregation. The SCell may be configured after radio resource control
(RRC) connection establishment and may be used to provide additional
radio resources. The PCell and the SCell may be used as a serving cell.
In the case of a UE which is in an RRC_connected state but in which CA is
not set or a UE which does not support CA, one serving cell composed of
only a PCell is present. In contrast, in the case of a UE which is an
RRC_connected state and in which CA is set, one or more serving cells may
be present and all the serving cells include a PCell and one or more
SCells. For carrier aggregation, after an initial security activation
process begins, a network may be added to a PCell initially configured in
a connection establishment process so as to configure a network including
one or more SCells for a UE supporting carrier aggregation. Accordingly,
the PCC corresponds to the PCell, primary (radio) resources and primary
frequency resources, which are used interchangeably. Similarly, the SCell
corresponds to the SCell, secondary (radio) resources and secondary
frequency resources, which are used interchangeably.

[0164] Hereinafter, methods of efficiently transmitting increased uplink
control information will be described with reference to the drawings.
More specifically, a new PUCCH format/signal processing
procedure/resource assignment method for transmitting increased uplink
control information is proposed. For description, the new PUCCH format
proposed by the present invention is referred to as PUCCH format 3 from
the viewpoint that up to a CA PUCCH format or PUCCH format 2 is defined
in the existing LTE release 8/9. The technical features of PUCCH format 3
proposed by the present invention are easily applicable to an arbitrary
physical channel (e.g., a PUSCH) for transmitting uplink control
information using the same or similar scheme. For example, the
embodiments of the present invention are applicable to a periodic PUSCH
structure for periodically transmitting control information or an
aperiordic PUSCH structure for aperiodically transmitting control
information.

[0165] The following drawings and embodiments will be described based on
the case in which a UCURS symbol structure of PUCCH format 1 (normal CP)
of LTE is used as a UCURS symbol structure of a subframe/slot level
applied to PUCCH format 3. The UCURS symbol structure of the
subframe/slot level in the shown PUCCH format 3 is defined for
convenience and the present invention is not limited to a specific
structure. In PUCCH format 3 according to the present invention, the
number and locations of UCI/RS symbols may be freely changed according to
system design. For example, PUCCH format 3 according to the embodiment of
the present invention may be defined using an RS symbol structure of
PUCCH format 2/2a/2b of LTE.

[0166] PUCCH format 3 according to the embodiment of the present invention
may be used to transmit uplink control information of an arbitrary kind
and/or size. For example, PUCCH format 3 according to the embodiment of
the present invention can be used to transmit information, such as HARQ
ACK/NACK, CQI, PMI, RI and/or SR, which may have a payload having an
arbitrary size. For convenience of description, the drawings and
embodiments will be described based on the case in which PUCCH format 3
according to the present invention is used to transmit ACK/NACK
information.

[0167] FIGS. 29 to 32 are diagrams illustrating a structure of PUCCH
format 3 according to the present invention and a signal processing
procedure therefor. In particular, FIGS. 29 to 32 show the structure of a
DFT-based PUCCH format. According to the DFT-based PUCCH structure, a
PUCCH is subjected to DFT precoding and time domain orthogonal cover (OC)
at an SC-FDMA level and is transmitted. Hereinafter, the DFT-based PUCCH
format is referred to as PUCCH format 3.

[0168] FIG. 29 shows the structure of PUCCH format 3 using an orthogonal
code (OC) with SF=4. Referring to FIG. 29, a channel coding block
performs channel coding with respect to transmission bits a_0, a_1, . . .
, and a_M-1 (e.g., multiple ACK/NACK bits) and generates encoded bits
(coded bits or coding bits) (or codewords) b_0, b_1, . . . , and b_N-1. M
denotes the size of the transmitted bits and N denotes the size of the
encoded bits. The transmitted bits include uplink control information
(UCI), for example, multiple ACK/NACK bits for a plurality of pieces of
data (or PDSCHs) received through a plurality of DL CCs. The transmitted
bits a_0, a_1, . . . , and a_M-1 are joint-coded regardless of the
kind/number/size of UCI configuring the transmitted bits. For example, if
the transmitted bits include multiple ACK/NACK bits for a plurality of DL
CCs, channel coding is performed not with respect to each DL CC or each
ACK/NACK bit, but with respect to all bit information. Thus, a single
codeword is generated. Channel coding is not limited thereto and includes
simplex repetition, simplex coding, Reed Muller (RM) coding, punctured RM
coding, tail-biting convolutional coding (TBCC), low-density parity-check
(LDPC) and turbo-coding. Although not shown, the encoded bits may be
subjected to rate matching in consideration of a modulation order and the
amount of resources. The rate matching function may be partially included
in the channel coding block or may be performed using a separate
functional block. For example, the channel coding block may perform (32,
0) RM coding with respect to a plurality of pieces of control information
so as to obtain a single codeword and perform circular buffer rate
matching.

[0169] A modulator modulates the encoded bits b_0, b_1, . . . , and b_N-1
and generates modulation symbols c_0, c_1, . . . , and c_L-1. L denotes
the size of the modulation symbols. The modulation method is performed by
changing the size and phase of the transmitted signal. The modulation
method includes, for example, n-phase shift keying (PSK) and n-quadrature
amplitude modulation (QAM) (n being an integer equal to or greater than
2). More specifically, the modulation method may include binary PSK
(BPSK), quadrature PSK (QPSK), 8-PSK, QAM, 16-QAM, 64-QAM, etc.

[0170] A divider divides the modulation symbols c_0, c_1, . . . , and
c_L-1 to slots. The order/pattern/method of dividing the modulation
symbols to slots is not specially limited. For example, the divider may
sequentially divide the modulation symbols to slots from the front side
(local type). In this case, as shown, the modulation symbols c_0, c_1, .
. . , and c_L/2-1 may be divided to a slot 0 and the modulation symbols
c_L/2, c_L/2+1, . . . , and c_L-1 may be divided to a slot 1. The
modulation symbols may be interleaved (or permutated) when being divided
to the slots. For example, even numbered modulation symbols may be
divided to slot 0 and odd numbered modulation symbols may be divided to
slot 1. The order of the modulation process and the division process may
be changed.

[0172] A spreading block spreads a signal subjected to DFT at an SC-FDMA
symbol level (time domain). Time domain spreading at the SC-FDMA symbol
level is performed using a spreading code (sequence). The spreading code
includes a quasi-orthogonal code and an orthogonal code. The
quasi-orthogonal code includes, but is not limited to, a pseudo noise
(PN) code. The orthogonal code may include, but is not limited to, a
Walsh code and/or a DFT code. Although the orthogonal code is described
as a representative example of the spreading code for ease of description
in the present specification, the orthogonal code is only exemplary and
may be replaced with a quasi-orthogonal code. A maximum value of a
spreading code size (or a spreading factor (SF)) is restricted by the
number of SC-FDMA symbols used to transmit control information. For
example, in the case in which four SC-FDMA symbols are used to transmit
control information at one slot, orthogonal codes w0, w1, w2 and w3
having a length of 4 may be used per slot. The SF means the spreading
degree of the control information and may be associated with the
multiplexing order of a UE or the multiplexing order of an antenna. The
SF may be changed to 1, 2, 3, 4, . . . according to system requirements
and may be defined between a BS and a UE in advance or may be sent to the
UE through DCI or RRC signaling. For example, in the case in which one of
SC-FDMA symbols for control information is punctured in order to transmit
an SRS, a spreading code with a smaller SF (e.g., SF=3 instead of SF=4)
may be applied to the control information of the slot.

[0173] The signal generated through the above procedure is mapped to
subcarriers within a PRB, is subjected to IFFT, and is transformed into a
time domain signal. The time domain signal is attached with CP and the
generated SC-FDMA symbols are transmitted through a RF stage.

[0174] On the assumption that ACK/NACK for five DL CCs is transmitted, the
procedure will be described in detail. In the case in which each DL CC
may transmit two PDSCHs, the number of ACK/NACK bits may be 12 if a DTX
state is included. In the case of assuming QPSK modulation and SF=4 time
spreading, a coding block size (after rate-matching) may be 48 bits. The
encoded bits may be modulated into 24 QPSK symbols and 12 symbols of the
generated QPSK symbols are divided to each slot. In each slot, 12 QPSK
symbols are converted into 12 DFT symbols by a 12-point DFT operation. In
each slot, 12 DFT symbols are spread and mapped to four SC-FDMA symbols
using the spreading code having SF=4 in a time domain. Since 12 bits are
transmitted through [2 bits*12 subcarriers+8 SC-FDMA symbols], the coding
rate is 0.0625 (=12/192). In case of SF=4, a maximum of four UEs may be
multiplexed per PRB.

[0176] The basic signal processing procedure is equal to that described
with reference to FIG. 29, except that the numbers and locations of UCI
SF-FDMA symbols and RS SC-FDMA symbols are different from those of FIG.
29. At this time, a spreading block may be provided at a previous stage
of a DFT precoder.

[0177] In FIG. 30, an RS may have the structure of an LTE system. For
example, cyclic shift is applicable to base sequence. Since a data part
has an SF of 5, a multiplexing capacity thereof is 5. A multiplexing
capacity of an RS part is determined according to cyclic shift (CS)
interval ΔshiftPUCCH. That is, the multiplexing capacity
of the RS part is

12 Δ shift PUCCH . ##EQU00002##

For example, multiplexing capacities are 12, 6 and 4 in the case in which
ΔshiftPUCCH=1, ΔshiftPUCCH=2 or
ΔshiftPUCCH=3, respectively. In FIG. 30, the multiplexing
capacity of the data part is 5 due to SF=5 and the multiplexing capacity
of the RS part is 4 in the case in which ΔshiftPUCCH is
3. Thus, the total multiplexing capacity is set to 4 which is the smaller
capacity of the two multiplexing capacities.

[0178] FIG. 31 shows the structure of PUCCH format 3 in which a
multiplexing capacity may be increased at a slot level.

[0179] SC-FDMA symbol level spreading described with reference to FIGS. 29
and 30 may be applied to an RS so as to increase a total multiplexing
capacity. Referring to FIG. 32, if a Walsh cover (or a DFT code cover) is
applied to a slot, the multiplexing capacity doubles. That is, even in
the case of ΔshiftPUCCH, the multiplexing capacity is 8
and the multiplexing capacity of the data part may not be deteriorated.
In FIG. 31, a Walsh cover of [y1 y2]=[1 1], [y1 y2]=[1 -1] or a linearly
transformed form thereof may be used as an orthogonal code cover (OCC)
for an RS.

[0180] FIG. 32 shows the structure of PUCCH format 3 in which a
multiplexing capacity may be increased at a subframe level.

[0181] If frequency hopping is not applied at a slot level, Walsh cover is
applied in slot units and thus the multiplexing capacity may double
again. As described above, [x1 x2]=[1 1] or [1 -1] may be used as an
orthogonal cover code and a modification thereof may be used.

[0182] For reference, the processing procedure of PUCCH format 3 is not
limited to the flowcharts shown in FIGS. 29 to 32.

[0183] Meanwhile, hereinafter, resource assignment will be described in
detail.

[0184]FIG. 33 is a diagram illustrating resource assignment indicated to
a UE. Control information of resource assignment may be provided to the
UE through a PDCCH downlink control information (DCI) format and may
indicate assignment of a physical resource block or assignment of a
virtual resource block according to a resource assignment type. FIG. 33
shows a method of continuously assigning frequency resources to uplink or
downlink transmission scheduled to the UE.

[0185] Table 11 shows a method of signaling a compact scheme of informing
the UE of a start point S of an RB which is a basic resource assignment
unit and the number (=length L) of assigned RBs when the UE is informed
of continuous frequency resource assignment as shown in FIG. 33. An
information field for resource block assignment may include a resource
indication valve (RIV) of Table 11. The start point of the RB and the
number (length) of continuously assigned RBs may be derived from the RIV.
In Table 11, .left brkt-bot.x.right brkt-bot. is a floor(x) operation and
indicates a maximum integer which is not greater than x.

[0186] As shown in FIG. 33, total frequency resources used for scheduling
of uplink or downlink transmission may be composed of NRB (0, . . .
, N-RB1) resource blocks (RBs). It is possible to inform the UE of
frequency resources assigned to the UE through the start point (RBstart)
S of the RB and the length (RBlength) L of the RB. The number of resource
assignment compositions (or the number of hypotheses) is
NRB(NRB+1)/2 and the number of assigned RB expressions (or the
number of hypotheses) is ceiling (log2(NRB+NRRB+1)/2).
Here, ceiling(x) denotes a minimum integer which is not less than x. As
shown in FIG. 33, if S is 0, the possible number (length) of RBs is
NRB and, if S is 1, the possible number (length) of RBs is
NRB-1. If S is NRB-1, the possible number (length) of RBs is 1.
That is, the start point S of the RB may have a value of
0≦S≦NRB-1 and the number (length; L) of assigned RBs
may be expressed by NRB-S. Alternatively, the length (L) of assigned
RBs may have a value of 1≦L≦NRB and the start point S
of the RB may be expressed by NRB-L.

[0187] If a bit field of scheduling control information is configured
according to binary numbers of the respective maximum values of the S and
L values without considering a combination of the S and L values, since
20<25 when NRB=20, 5 bits are required for each of the S and
L values, that is, a total of 10 bits is required. However, the
configuration of the bit field includes combinations which do not
actually occur and thus unnecessarily increases the number of transmitted
bits. Accordingly, only combinations of the S and L values, which may be
achieved for reducing the number of transmitted bits, may be represented
by the RIV and the RIV may be represented by a binary number and
transmitted. For example, in the case of NRB=20, the possible
combinations of the S and L values may be shown in Table 12. In Table 12,
1≦L≦20 when S=0, 1≦L≦19 when S=1,
1≦L≦18 when S=2 , 1≦L≦2 when S=18 and L=1
when S=19. That is, in Table 12, a hatched part corresponds to a
combination of the S and L values which does not occur.

[0188] If the RIV value is configured in such a manner, the RIV of the
hatched part of Table 12 in the case of L-1≦.left
brkt-bot.NRB/2.right brkt-bot. may be mapped to the RIV in the case
of L-1≦.left brkt-bot.NRB/2.right brkt-bot., thereby
preventing the RIV from being wasted. For example, in the case of
NRB=20, the RIVs of the part of L≦.left
brkt-bot.NRB/2.right brkt-bot.+1=.left brkt-bot.20/2.right
brkt-bot.+1=11 in the hatched region of Table 12 may be reused for the
part of L≦.left brkt-bot.NRB/2.right brkt-bot.+1=.left
brkt-bot.20/2.right brkt-bot.+=11 in the remaining region. At this time,
a maximum value of the RIV representing the possible combination of the S
and L values becomes 209.

[0189] If the RIV value is configured in such a manner, the number of
transmitted bits depends on the maximum value of the RIV and the RIV
equal to or less than the maximum value of the RIV may be configured not
to be mapped to a value which cannot become the actual combination of the
S and L values. That is, all values equal to or less than the maximum
value of the RIV may correspond to combinations of the S and L values
which may occur. Thus, since the possible combinations of the S and L
values are represented by 209 (=NRB(NRB+1)/2-1, NRB=20)
states, the RIV may be represented by only 8 bits.

[0190] Meanwhile, as shown in the bottom of Table 11, if the maximum value
(=Llimit) of the number of assigned RBs is restricted in the RIV
configuration method, that is, if the L value is restricted to be equal
to or less than Llimit, the number of bits necessary to represent
the combinations of the S and L values may be reduced. For example, if
Llimit=6 is set in Table 12, the range of the L value is
1≦L≦6 and the range of the L value of 7≦L≦20
is not used. Thus, it can be seen that the maximum value of the RIV is
114. That is, since the range of the generable RIV is
0≦RIV≦114<27,
Nbit--required--lim7 bits.

[0191] In addition, semi-persistent scheduling (SPS) will be described in
detail.

[0192] SPS means a scheduling scheme for setting parameters (a subframe
period and an offset) associated with a subframe, in which SPS
transmission/reception may be performed in uplink or downlink, through
radio resource control (RRC) signaling with respect to a UE and informing
the UE of actual SPS activation and release through a PDCCH. In other
words, even when the UE receives information about a subframe, in which
SPS transmission/reception will be performed, through RRC signaling, SPS
transmission/reception is not immediately performed but SPS
transmission/reception is performed after a PDCCH (that is, a PDCCH in
which SPS C-RNTI is detected) indicating SPS activation/release is
received. In addition, the UE may start to perform SPS
transmission/reception according to the subframe period and offset
received through RRC signaling by assigning frequency resources to be
used for SPS transmission/reception according to resource block
assignment information and a modulation and coding scheme (MCS) specified
through the PDCCH indicating SPS activation and applying a modulation
scheme and a coding rate. In addition, the UE may stop SPS
transmission/reception by receiving the PDCCH indicating SPS release. In
addition, if the UE receives a PDCCH indicating activation (or
reactivation) with respect to the stopped SPS transmission/reception, SPS
transmission/reception may be resumed with the subframe period and offset
received through RRC signaling according to RB assignment and MCS
specified in the PDCCH.

[0194] The PDCCH for SPS scheduling may be validated by masking, for
example, CRC of the DCI transmitted via the PDCCH with SPS C-RNTI and
setting NDI to 0. That is, in the case of SPS activation, by setting a
combination of specific bit fields to 0, it is possible to validate SPS
activation control information. Table 13 shows specific fields which may
be used to validate the PDCCH indicating SPS activation according to DCI
format.

TABLE-US-00013
TABLE 13
DCI format DCI format DCI format
0 1/1A 2/2A/2B
TPC command for set N/A N/A
scheduled PUSCH to `00`
Cyclic shift DM RS set N/A N/A
to `000`
Modulation and MSB is set N/A N/A
coding scheme and to `0`
redundancy version
HARQ process N/A FDD: set FDD: set
number to `000` to `000`
TDD: set TDD: set
to `0000` to `0000`
Modulate and N/A MSB is set For the enabled
coding scheme to `0` transport block:
MSB is set to `0`
Redundancy version N/A set For the enabled
to `00` transport block:
set to `00`

[0195] A method of determining whether a combination of specific bit
fields has a predetermined value so as to determine whether errors occur
is represented by a method of using the combination of specific bit
fields as virtual CRC. In other words, by using virtual CRC, even when
errors which cannot be confirmed by CRC occur, it is possible to detect
additional errors by determining whether the bit field value has the
predetermined value.

[0196] Error detection using a virtual CRC is particularly important in
SPS activation/release. For example, if error occurs in PDCCH detection
of a certain UE and the certain UE erroneously recognizes DCI, which was
assigned to another UE, as a PDCCH indicating SPS activation thereof, the
certain UE continuously uses SPS transmission resources and thus causes a
continuous problem due to the error. Accordingly, it is possible to
prevent erroneous SPS detection using a virtual CRC.

[0197] In the case of SRS release, in order to confirm collection of
resources assigned to the UE, the UE may transmit ACK/NACK for reception
of the PDCCH indicating SPS release. In the case of SRS release, as shown
in FIG. 14, the value of the specific bit field may be set according to
DCI format and is used as virtual CRC.

TABLE-US-00014
TABLE 14
DCI format 0 DCI format 1A
TPC command for set to `00` N/A
scheduled PUSCH
Cyclic shift DM RS set to `000` N/A
Modulation and set to `11111` N/A
coding scheme and
redundancy version
Resource block Set to all `1`s N/A
assignment and hopping
resource allocation
HARQ process N/A FDD: set to `000`
number TDD: set to `0000`
Modulation and N/A set to `11111`
coding scheme
Redundancy version N/A set to `00`
Resource block N/A Set to all `1`s
assignment

[0198] Next, a downlink assignment index of a TDD system will be described
in detail.

[0199] PDCCH DCI formats 0, 1, 1A, 1B, 1D, 2 and 2A may include a downlink
assignment index (DAI) field. The DAI field includes information about
the accumulated number of PDSCHs transmitted by the BS and/or PDCCHs
without PDSCHs corresponding thereto within one or more downlink
subframes for ACK/NACK transmission in one uplink subframe in a TDD
system, and the UE may derive information about the number of PDSCHs
transmitted by the BS and/or PDCCHs without PDSCHs corresponding thereto
in transmission of uplink ACK/NACK in one uplink subframe for the PDSCHs
within one or more downlink subframe and/or PDCCHs without PDSCHs
corresponding thereto using the information. The UE may determine whether
a transmission which is not detected is present in the PDSCHs transmitted
by the BS and/or PDCCHs without PDSCHs corresponding thereto within one
or more downlink subframes for ACK/NACK transmission in one uplink
subframe. Hereinafter, the DAI field will be described in greater detail.

[0200] An FDD scheme refers to a scheme for dividing downlink and uplink
according to independent frequency bands to perform transmission and
reception. Accordingly, if a BS sends a PDSCH or a PDCCH without a PDSCH
corresponding thereto using a DL band, a UE may transmit an ACK/NACK
response indicating whether DL data has been received through a PUCCH of
a UL band corresponding to the DL band after a specific time.
Accordingly, operation is performed in a state in which DL and UL are in
one-to-one correspondence.

[0201] More specifically, in the example of the conventional 3GPP LTE
system, control information of downlink data transmission of a BS is sent
to a UE through a PDCCH and the UE which receives data, through the
PDCCH, scheduled thereto through a PDSCH may transmit ACK/NACK through a
PUCCH which is a channel for transmitting uplink control information (or
using a piggyback method on a PUSCH). In contrast, the PDCCH may be used
for a special purpose without a PDSCH for data scheduled through the
PDCCH. For example, a PDCCH indicating downlink SPS release does not have
a PDSCH corresponding thereto. In a 3GPP LTE system, a UE which receives
a PDCCH not having a PDSCH corresponding thereto may transmit ACK/NACK
through a PUCCH which is a channel for transmitting uplink control
information (or a piggyback method on a PUSCH). In addition, in TDD,
ACKs/NACKs for PDSCHs which extend over one or more downlink subframes
and PDCCHs without PDSCHs corresponding thereto may be collected,
processed and transmitted via a PUCCH of one uplink subframe. For clarity
of description, in the following description, if the PDCCH does not cause
confusion with another PDCCH, the PDCCH means a PDCCH for scheduling a
PDSCH. That is, if another meaning is not described, the PDCCH for
scheduling the PDSCH is expressed as a PDCCH. In addition, a description
of the PDCCH without the PDSCH corresponding to an ACK/NACK response
through a PUCCH will be omitted for convenience. In general, a PUCCH for
ACK/NACK transmission is not assigned to UEs in advance and a plurality
of UEs within a cell may divide and use a plurality of PUCCHs at each
point of time. Accordingly, a UE which receives downlink data at an
arbitrary point of time may use a PUCCH corresponding to a PDCCH, via
which the UE receives scheduling information of downlink data, as a PUCCH
for transmitting ACK/NACK.

[0202] A PUCCH corresponding to a PDCCH will be described in greater
detail. A region in which a PDCCH of each downlink subframe is
transmitted is composed of a plurality of control channel elements (CCEs)
and a PDCCH transmitted to one UE in an arbitrary subframe is composed of
one or a plurality of CCEs configuring a PDCCH region of the subframe. In
addition, resources used to transmit a plurality of PUCCHs are present in
a region in which a PUCCH of each uplink subframe is transmitted. At this
time, the UE may transmit ACK/NACK through PUCCH resources corresponding
to an index of a specific (that is, first) CCE among CCEs configuring the
PDCCH received by the UE.

[0203]FIG. 34 is a diagram showing resources used to transmit ACK/NACK
for a PDSCH. In FIG. 34, each rectangle of a DL CC denotes a CCE and each
rectangle of a UL CC denotes PUCCH resource. As shown in FIG. 34, for
example, assume that one UE obtains information about a PDSCH through a
PDCCH composed of fourth, fifth and sixth CCEs and receives a PDSCH. In
this case, the UE may transmit ACK/NACK information for the PDSCH through
a PUCCH corresponding to the fourth CCE which is a first CCE configuring
the PDCCH for scheduling the PDSCH, that is, the fourth PUCCH resource.

[0204] Unlike the FDD scheme, in a system according to a TDD scheme, the
same frequency band is assigned to DL subframes and UL subframes on a
time axis. In an asymmetrical data traffic state of DL/UL, DL subframes
greater in number than the number of UL subframes are assigned or UL
subframes greater in number than the number of DL subframes are assigned.
In this case, unlike the FDD scheme, the DL subframes and the UL
subframes are not in one-to-one correspondence. In particular, if the
number of DL subframes is greater than the number of UL subframes, an
ACK/NACK response to a plurality of PDSCHs transmitted on a plurality of
DL subframes needs to be processed at one UL subframe.

[0205] When a plurality of PDSCHs is transmitted to one UE on a plurality
of DL subframes, a BS transmits a plurality of PDCCHs one by one with
respect to each PDSCH. At this time, the UE may transmit ACK/NACK through
one PUCCH on one UL subframe with respect to the plurality of PDSCHs. A
method of transmitting one ACK/NACK with respect to a plurality of PDSCHs
may be roughly divided into an ACK/NACK bundling method and a PUCCH
selective transmission method.

[0206] In the ACK/NACK bundling method, if all of the plurality of PDSCHs
received by the UE are successfully decoded, the number of pieces of ACK
information is transmitted through one PUCCH. In the other case (that is,
if decoding of at least one of the plurality of PDCCHs fails), NACK is
transmitted. Hereinafter, in order to prevent confusion, the ACK/NACK
bundling method is referred to as a bundling method. The bundling method
may be used such that the number of ACKs is transmitted if at least one
of a plurality of PDSCHs is successfully decoded and, otherwise (that is,
decoding of all a plurality of PDSCHs fails), NACK is transmitted.
Alternatively, the bundling method may be used such that the number of
continuous ACKs from a first PDSCH is transmitted through one PUCCH if at
least one of a plurality of PDSCHs received by the UE is successfully
decoded and, otherwise (that is, decoding of a first PDSCH of a plurality
of PDSCHs fails), NACK is transmitted.

[0207] In the PUCCH selective (or channel selective) transmission method,
a UE which receives a plurality of PDSCHs may occupy a plurality of
PUCCHs which may be used for ACK/NACK transmission using an arbitrary
method, and transmit a plurality of ACKs/NACKs using a combination of
information indicating which of the plurality of occupied PUCCHs is used
for ACK/NACK transmission (that is, an information bit is used to
indicate which channel is selected) and modulated/encoded information of
the selected and transmitted PUCCH. For example, if one of two PUCCHs is
selected and ACK/NACK information having a bit size of a is transmitted
on the selected PUCCH, since information about of a bit size of 1 may be
expressed by selecting one of two PUCCHs, ACK/NACK information having a
bit size of a+1 may be transmitted.

[0208] In transmission of an ACK/NACK signal from a UE to a BS using the
above-described methods, assume that the UE does not receive (that is,
miss) some of the PDCCHs sent by the BS during several subframes. In this
case, since the UE does not know that the PDSCH corresponding to the
missing PDCCH is transmitted to the UE, an error may occur in ACK/NACK
generation.

[0209] In order to solve such an error, in a TDD system, a method of
including a downlink assignment index (DAI) in a PDCCH and informing a UE
of the number of PDSCHs to be transmitted through ACK/NACK resources of
one UL subframe is defined. For example, one UL subframe corresponds to N
DL subframes, indices are sequentially assigned (that is, sequentially
counted) to PDSCHs transmitted on N DL subframes to carry PDCCHs for
scheduling the PDSCHs. Then, the UE may be aware that the previous PDCCHs
have been received using the DAI included in the PDCCH.

[0210] In a TDD system, DAI information may be used as a pure counter.
That is, an assignment order of downlink control channels for a specific
UE may be represented by 2 bits. Each UE receives an assignment order of
a downlink control channel on a plurality of subframes and confirm a DAI
value in the assignment order of the downlink control channel. If
previously received DAI values are not continuous, the UE may be aware of
missing assignment. Missing assignment means that the UE cannot detect or
demodulate a PDCCH assigned thereto.

[0211] At this time, the DAI value may be expressed by Equation 3 below.

I=mod(P,N) [Equation 3]

[0212] where, I denotes each DAI value, P denotes an assignment order of
downlink assignment index information, N denotes 2n, and n denotes
the number of bits indicating the DAI information.

[0213] For example, if the number n of bits indicating the DAI information
is 2 and the assignment order P is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10, N
has a value of 4 and each DAI value is 0, 1, 2, 3, 0, 1, 2, 3, 0, 1 and
2.

[0214] Referring to FIG. 35, an ACK/NACK signal transmitted when a UE does
not receive one of a plurality of PDCCHs in a TDD system will be
described. In FIG. 35, one UL subframe corresponds to three DL subframes.

[0215] FIG. 35(b) shows the case in which a UE has missed a second PDCCH.
That is, the UE receives a PDCCH having DAI=1 and then receives a PDCCH
having DAI=3. At this time, since the DAI (=3) of a third PDCCH which is
a last PDCCH and the number (that is, two) of PDCCHs received up to that
time is different, the UE recognizes that the second PDCCH has been
missed and thus transmits ACK/NACK.

[0216] FIG. 35(c) shows the case in which the UE has missed a third PDCCH.
That is, the UE receives a PDCCH having DAI=1 and a PDCCH having DAI=2
but does not receive a PDCCH having DAI=3. At this time, since the DAI
index of the last received PDCCH and the number of PDCCHs received up to
that time are identical, the UE may not recognize that the last PDCCH has
been missed. Accordingly, the UE may recognize that only two PDCCH are
scheduled during a DL subframe. At this time, since ACK/NACK information
is transmitted as PUCCH resources corresponding to DAI=2 instead of PUCCH
resources corresponding to DAI=3, a BS may discern that a PDCCH having
DAI=3 has been missed.

[0217] Hereinafter, various methods of, at a UE, transmitting an ACK/NACK
signal with respect to a plurality of PDCCHs scheduled in a multi-carrier
system will be described in detail.

[0218] When a plurality of PDCCHs for scheduling transmission of a
plurality of PDSCHs is transmitted in a multi-carrier system, if the UE
has not received (that is, missed) at least one of the plurality of
PDCCHs, ACK/NACK generation errors may occur. In order to solve this
problem, a method of informing the UE of the total number of PDCCHs for
scheduling PDSCHs or order information of PDCCHs may be considered. In
order to inform the UE of such information, a DAI field defined in a
PDCCH DCI format may be used. Conventionally, DAI information is defined
in a TDD system. However, in the present invention, in both TDD and FDD
systems, DAI information for PDSCH scheduling may be configured in a
multi-carrier system. In the following description, a PDCCH for
scheduling a PDSCH is referred to as a PDCCH if it does not have another
meaning. An ACK/NACK response is actually a response to a PDCCH and is
used interchangeably with a PDCCH for scheduling a PDSCH for convenience.
A PDCCH requiring an ACK/NACK response without a PDSCH corresponding
thereto and a PDCCH for scheduling a PDSCH are indiscriminately described
for convenience.

[0219] In addition, a method of including information indicating the
number of PDSCHs transmitted to a UE with respect to PDCCHs (that is, the
total number of PDSCHs transmitted to the UE) will be described with
reference to FIG. 36.

[0220] As described above, a PDCCH means a PDCCH for scheduling a PDSCH
and one PDCCH schedules one PDSCH transmission. Thus, the number of
PDCCHs is equal to the total number of PDSCHs scheduled to the UE. If
transmission of a PDCCH without a PDSCH corresponding thereto is
included, the number of PDCCHs may be greater than the total number of
PDSCHs scheduled to the UE by a predetermined number. For convenience of
description, transmission of a PDCCH without a PDSCH corresponding
thereto will be omitted. As shown in FIG. 36(a), in PDCCHs and PDSCHs
transmitted by a BS (eNB), three PDCCHs may schedule transmission of a
total of three PDSCHs, respectively. In addition, when the eNB transmits
a plurality of PDCCHs to an arbitrary UE on one subframe (that is,
including cross-carrier scheduling), the UE may be informed of
information indicating the number of PDCCHs received on the subframe.
Alternatively, in TDD, the eNB transmits a plurality of PDCCHs to an
arbitrary UE on one or more downlink subframes corresponding to one
uplink subframe for an ACK/NACK response, the UE may be informed of
information indicating the number of PDCCHs received for an ACK/NACK
response on the uplink subframe via each PDCCH. The UE may be informed of
the number of PDCCHs through a DAI field of a PDCCH DCI format. FIG.
36(b) shows the case in which the UE fails to detect one of a plurality
of PDCCHs. FIGS. 36(c) and 11(d) show various methods of setting a
plurality of ACK/NACK resources. FIGS. 36(c) and 36(d) show an example in
which a plurality of PUCCHs is set in a UE-specific manner and ACK/NACK
information for a plurality of PDSCHs is transmitted via one PUCCH
resource, an example in which ACK/NACK information for a plurality of
PDSCHs is transmitted through one PUCCH resources on an extended PUCCH,
and an example in which ACK/NACK information for a plurality of PDSCHs is
transmitted on a PUSCH.

[0221] For example, if an eNB transmits three PDCCHs to one UE on one or
more DL subframes corresponding to one uplink subframe for an ACK/NACK
response, information indicating that three PDCCHs are transmitted may be
transmitted to the UE in a state of being included in the three PDCCHs.
FIGS. 36(a) and 36(b) show the case that a DAI field included in each
PDCCH has a value of 3 (the number of PDCCHs or the number of PDSCHs). In
this method, if the UE has missed at least one of the plurality of PDCCHs
transmitted thereto, the UE can confirm the fact that the UE has missed
the PDCCH through the information about the number of PDCCHs included in
other PDCCHs received by the UE.

[0222] In this method, if the UE detects only two PDCCHs among three
PDCCHs (FIG. 36(b)), the UE may confirm that the eNB has transmitted
three PDCCHs but the UE has received only two PDCCHs through the
information about the number of PDCCHs. However, the UE may not confirm
which of the PDCCHs has been missed. For example, if ACK/NACK for PUCCHs
corresponding to CCE indices of PDCCHs is transmitted, since ACK/NACK for
a PUCCH corresponding to the CCE index of the missing PDCCH is not
transmitted, the eNB may recognize which of the PDCCHs has been missed by
the UE. However, if PUCCH resources for ACK/NACK transmission are
assigned to the UE in advance independently of PDCCHs and the assigned
PUCCH resources are arranged in order of the received PDCCHs, the UE is
not aware of the order of the missing PDCCH and thus PUCCH resource
assignment is not accurately performed when PDCCH reception errors occur.
Similarly, even when ACK/NACK information is transmitted on PUSCH
resources using a piggyback method, since the UE is not aware of the
order of the missing PDCCH, ACK/NACK resource mapping may not be
performed.

[0223] More specifically, as shown in FIG. 36(b), if the UE has detected
only two of the three PDCCHs and has failed to detect one PDCCH, the UE
is aware that a total of three PDCCH has been transmitted (that is, a
total of PDSCHs has been scheduled) but is not aware which of the PDCCHs
has been missed. In this case, as shown in FIG. 36(c), if three ACK/NACK
transmission resources are assigned in advance, a determination as to
which ACK/NACK transmission resource corresponds to which PDSCH
transmission may not be made. That is, the UE may not determine to which
of three ACK/NACK transmission resources ACK/NACK information for PDSCHs
scheduled by the two received PDCCHs correspond. Similarly, the eNB may
not determine to which of the PDSCHs the ACK/NACK information mapped to
any two of the three ACK/NACK transmission resources corresponds.

[0224] Accordingly, in preparation for PDCCH detection failure, if the UE
may obtain ACK/NACK resources corresponding in number to the number of
PDSCHs which may be maximally scheduled by the eNB at a specific time and
the ACK/NACK resources are mapped according to the order of CCs at which
PDSCHs are located (or the order of subframes or the two-dimensional
order of CCs and subframes), the above-described problems may be solved.
For example, as shown in FIG. 36(d), the UE which has received two of the
three PDCCHs can confirm that the total number of scheduled PDSCHs is 3.

[0225] The UE may confirm that transmission of PDSCHs on first and second
CCs have been scheduled by the two received PDCCHs (although a
determination as to which PDCCH has been missed is not made). For
example, the UE may map ACK/NACK information for each PDSCH to a first
ACK/NACK transmission resource with respect to a PDSCH on a first CC and
map ACK/NACK information for each PDSCH to a second ACK/NACK transmission
resource with respect to a PDSCH on a second CC. Similarly, the eNB may
confirm a CC on which the PDSCH, to which the ACK/NACK transmitted by the
UE corresponds, is transmitted.

[0226] A method of including information indicating an order value of a
PDCCH transmitted to the UE (that is, an order value of a PDSCH
transmitted to the UE) in each PDCCH will be described with reference to
FIG. 37.

[0227] When the eNB transmits one or a plurality of PDCCHs to an arbitrary
UE on one or more DL subframes corresponding to one UL subframe for an
ACK/NACK response, the eNB may inform the UE of the order value of the
PDCCH transmitted on the subframe. For example, as shown in FIG. 37(a),
if the eNB transmits three PDCCHs to one UE on one subframe, each value
of 1, 2 or 3 (or 0, 1 or 2) may be included in each PDCCH as the order
value of the PDCCH. Such an order value may be transmitted via a DAI
field of each PDCCH DCI format. The order of PDCCHs may be determined
according to the order of one or more DL subframes corresponding to
ACK/NACK transmission of one UL subframe, the size of a CCE index
configuring a PDCCH, the frequency order of CCs on which the PDSCHs are
transmitted, or the order of carrier indication field (CIF) values of
CCs.

[0228] For example, if the UE has received only a PDCCH having an order
value of 1 and a PDCCH having an order value of 3 on one or more DL
subframes corresponding to one UL subframe for an ACK/NACK response, the
UE may confirm that a PDCCH having an order value of 2 and a PDSCH
corresponding thereto has been missed. That is, unlike the
above-described method, the UE may confirm the order of the received
PDCCHs and thus confirm the index of the missing PDCCH. However, as shown
in FIG. 37(b), if a last PDCH has been missed, since the order values 1
and 2 of the already received PDCCHs match the order of the received
PDCCHs, the UE may not confirm that the last PDCCH has been missed. Thus,
the eNB cannot confirm how many PDCCHs have been transmitted to the UE.

[0229] In addition, the case in which bundled ACK/NACK for all PDSCHs is
transmitted through the PUCCH corresponding to the CCE index of the PDCCH
which was last received by the UE may be considered. At this time, if the
UE has missed the last PDCCH when the eNB has assigned three PDCCHs to
the UE, the UE recognizes that two PDSCHs scheduled by the received
PDCCHs have been normally received and transmits ACK/NACK information
through PUCCH resources corresponding to a second PDCCH. Then, the eNB
can confirm that ACK/NACK has been transmitted through the PUCCH
corresponding to the second PDCCH, not through the PUCCH corresponding to
the last PDCCH, and recognize that the UE has missed the last PDCCH.
Meanwhile, if the bundled ACK/NACK is transmitted through PUCCH resources
assigned in a UE-specific manner, not through the PUCCH corresponding to
the CCE on which the PDCCH is transmitted and the UE transmits the
bundled ACK/NACK for the first two PDCCHs through the allocated PUCCHs,
the eNB may not confirm whether the ACK/NACK corresponds to two PDSCHs or
three PDSCHs.

[0230] In addition, if the total number of transmitted PDSCHs (or the
number of PDCCHs for scheduling the PDSCHs) is not provided to the UE,
ACK/NACK resources corresponding in number to the number of PDSCHs which
are maximally scheduled needs to be secured. As shown in FIG. 37(c), for
example, if a maximum of four PDSCHs may be scheduled, ACK/NACK resources
which may be used to transmit the four PDSCHs must always be secured and
transmitted. In this case, since unnecessary resources are secured in
advance when multiple ACKs/NACKs are fed back on the PUSCH or when
multiple ACKs/NACKs are transmitted via the PUCCH format, ACK/NACK
information bits are increased and thus a coding rate may not be
efficiently reduced.

[0231] Hereinafter, a process of reporting control information at a UE in
a multi-carrier system or a carrier aggregation system will be described.

[0232] Conventionally, the UE reports control information in consideration
of a single layer and a single component carrier for uplink. However, in
the multi-carrier or carrier aggregation system, there is a need for an
efficient method supporting a plurality of component carriers.

[0233] Prior to a detailed description of the present invention, ACK/NACK
information reported to an eNB will be described in detail.

[0234] First, ACK/NACK information may be information about a PDSCH
indicated by a PDCCH transmitted from the eNB to the UE.

[0235] Next, ACK/NACK information may be information about a PDCCH
indicating semi-persistent scheduling (SPS) release. At this time,
ACK/NACK information may not include information about SPS activation. In
addition, ACK/NACK information for the PDCCH indicating SPS release may
be present only in a primary cell (PCell).

[0236] In addition, ACK/NACK information may be information about a PDSCH
assigned by SPS. At this time, the ACK/NACK may be present only in a
primary cell (PCell).

[0237] Accordingly, the ACK/NACK information may be information about a
PDCCH, information about a PDSCH indicated by a PDCCH or information
about a PDSCH assigned by SPS.

[0238] Hereinafter, for convenience of description, assume that ACK/NACK
information is information about a PDCCH. The ACK/NACK information may
include, but is not limited to, information about a PDSCH indicated by
the above-described PDCCH, information about a PDSCH assigned by SPS,
etc. The present invention is applicable to a variety of ACK/NACK
information.

[0239] As described above, a bundling method may be used as a scheme for
transmitting one ACK/NACK with respect to a plurality of PDSCHs.

[0240] At this time, the bundling method includes a full bundling method
and a partial bundling method.

[0241] The full bundling method means a scheme for bundling a plurality of
subframes and a plurality of component carriers within a predetermined
time domain. At this time, the full bundling method may include a spatial
bundling method for bundling codewords.

[0242] The partial bundling method means a scheme for bundling any one of
subframes or component carriers. At this time, any one of the subframes
or the component carriers may be bundled.

[0243] That is, the partial bundling method includes a CC domain partial
bundling method for bundling component carriers on a per subframe basis
and a time domain partial bundling method for bundling a plurality of
subframes on a per component carrier basis.

[0244] A specific system may support any one or both of the full bundling
method and the partial bundling method.

[0245]FIG. 38 is a diagram illustrating a full bundling method according
to an embodiment of the present invention.

[0246] In FIG. 38, a DAI is used as a pure counter. That is, an assignment
order of a downlink control channel for a specific UE is represented by 2
bits and is represented by a DAI value obtained by modulo 4 operation
using Equation 3.

[0247] Referring to FIG. 38, a plurality of subframes and a plurality of
component carriers are indiscriminately bundled in a time domain.

[0248] FIG. 39 is a diagram illustrating a partial bundling method
according to an embodiment of the present invention.

[0249] FIG. 39(a) shows a time domain partial bundling method. Referring
to FIG. 39(a), all or some of the plurality of subframes are bundled on a
per component carrier basis.

[0250] Next, FIG. 39(b) shows a component carrier partial bundling method.
Referring to FIG. 39(b), all or some of component carriers may be bundled
on a per subframe basis.

[0251] In association with the full bundling method, as shown in FIG. 38,
the UE may detect a PDCCH and conform whether there is a missing PDCCH
from continuity of the DAI value.

[0252] If a last PDCCH has been missed within a subframe, it is difficult
for the UE to determine whether there is a missing PDCCH. At this time,
last one PDCCH may be missed or a plurality of last consecutive PDCCHs
may be missed.

[0253] Accordingly, the UE may report information about the last PDCCH
detected by the UE (e.g., the DAI value of the last detected PDCCH), the
number of PDCCHs detected by the UE, information about the number of ACK
responses for the detected PDCCHs, etc. to the eNB in addition to the
bundled ACK/NACK information (DTX may be separately identified or may be
treated as being equal to NACK). Thus, the eNB may accurately confirm the
PDCCH detection state of the UE.

[0254] In order to distinguish between the information about the last
detected PDCCH, the number of detected PDCCHs or the information about
the number of ACK responses for the detected PDCCHs and the bundled
ACK/NACK information, the two pieces of information may be composed of
separate bits and may be mapped to a constellation point and reported by
complexly taking account of the two pieces of information.

[0255] For example, if the last detected DAI (2 bits) is reported in
addition to the bundled ACK/NACK information, 2 bits for the last
detected DAI value may be additionally used in addition to 1 bit for the
bundled ACK/NACK information.

[0256] In addition, if the bundled ACK/NACK information and the last
detected DAI value are complexly mapped to constellation points, mapping
may be reported using QPSK through repeated mapping of a specific DAI
value. For example, (0, 0) may be transmitted if the bundled ACK/NACK
information is NACK, (0, 1) may be transmitted if the bundled ACK/NACK
information is ACK and the last DAI value is 0 or 3, (1, 0) may be
transmitted if the bundled ACK/NACK information is ACK and the last DAI
value is 1, and (1, 1) may be transmitted if the bundled ACK/NACK
information is ACK and the last DAI value is 2.

[0257] However, in this case, the following problems occur.

[0258] That is, if the last DAI value is 0 or 3 and the assignment orders
of last three continuous downlink control channels of a plurality of
PDCCHs have been missed, since repeated information is mapped to the
constellation points, it is difficult for the eNB to recognize this
state.

[0259] In addition, if the information is transmitted to the eNB using
QPSK according to the above-described method, a minimum distance between
information is greater than BPSK and thus performance deterioration
occurs.

[0260] If information is transmitted using QPSK according to the
above-described method, since the ACK/NACK state does not have the same
part in the constellation (e.g., NACK is located at one place and ACKs
are located at three places in the constellation), performance
deterioration may occur.

[0261] The purpose of the full bundling method is to use fewer transmit
bits with respect to the transmit power of the UE. Thus, such performance
deterioration through QPSK constellation may cause a problem.

[0262] Accordingly, the present invention proposes a method of assigning
PUCCH resources to a UE according to information about a last detected
PDCCH in order to improve performance of an ACK/NACK full bundling method
while efficiently supporting a plurality of component carriers in a
mobile communication system.

[0263] The below-described bundling means a logical AND operation, which
is merely exemplary. Bundling may be performed through other methods such
as a logical OR operation. That is, in the following description of the
present invention, bundling means a method of representing a plurality of
ACK/NACKs using a small bit number (that is, a method of representing
ACK/NACK information of M bits using N bits (M=>N)).

[0264] In addition, for convenience of description, although the present
invention is applicable to TDD or FDD, TDD is assumed.

[0265] In addition, although ACK and NACK are described in association
with control information, the DTX state may be mapped to NACK in the
present invention.

[0266] The present invention is not limited to application or application
order of the above-described spatial bundling method.

[0267] For example, spatial bundling may first be performed within a
specific subframe and a specific component carrier (CC) and then full
bundling or partial bundling may be performed with respect to the
spatial-bundled ACK/NACK information.

[0268] As another example, full bundling or partial bundling may be
performed with respect to the spatial-bundled ACK/NACK information and
then additional spatial bundling may be performed. Hereinafter, for
convenience of description, assume that spatial bundling is first
performed within a specific subframe and a specific component carrier
(CC).

[0269] In addition, hereinafter, assume that a primary cell (PCell) can
confirm assigned PUCCH resources according to an implicit or explicit
method. For example, as an implicit method, assigned PUCCH resources may
be determined through a CCE index of a PDCCH. In addition, as an explicit
method, PUCCH resources may be assigned in advance through RRC signaling.
A method of assigning PUCCH resources to the primary cell is not limited
to the above-described examples.

[0270] Next, assume that a secondary cell (SCell) can confirm assigned
PUCCH resources according to an implicit or explicit method. For example,
as an implicit method, assigned PUCCH resources may be determined through
a CCE index of a PDCCH. In addition, as an explicit method, assigned
PUCCH resources may be determined through a variable such as an
assignment resource indicator (ARI) or PUCCH resources may be assigned in
advance through RRC signaling. A method of assigning PUCCH resources to
the secondary cell is not limited to the above-described examples.

[0271] In the present invention, different bundling methods may be used
according to the number of codewords included in the PDCCH.

[0272] Hereinafter, the bundling method according to the number of
codewords included in the PDCCH will be described in detail.

[0273] In addition, although it is assumed that the maximum number of
codewords which may be included in the PDCCH is two for convenience of
description, the present invention is not limited thereto.

[0274] (1) Case in which each of a plurality of detected PDCCHs includes
one codeword

[0275] At this time, the UE may perform full bundling without any
particular problem. At this time, the bits of the bundled ACK/NACK
information may be transmitted in the form of PUCCH format 1a.

[0276] (2) Case in which at least one of a plurality of detected PDCCHs
includes two codewords

[0277] First, the UE may perform spatial bundling with respect to two
codewords. Thereafter, the UE performs full bundling with respect to
ACK/NACK information for 1 codeword and spatial-bundled ACK/NACK
information. The finally bundled ACK/NACK information bits may be
transmitted in the form of PUCCH format 1a.

[0278] Meanwhile, other methods may be used. That is, if any PDCCH
includes one codeword, in order to process the PDCCH as including two
codewords, ACK/NACK information may extend to two bits according to a
predetermined rule.

[0279] At this time, assume that the PDCCH carries a maximum number of
transport blocks. If the PDCCH carries a maximum number or less of
transport blocks, control information of the transport blocks excluding
the transport blocks actually carried by the PDCCH among the maximum
number of transport blocks may be regarded as NACK information and may be
processed to have the same value as the control information of the
actually carried transport blocks.

[0280] For example, NACK information may be added to the ACK/NACK
information for the PDCCH having one codeword so as to configure virtual
2-bit ACK/NACK information. Thereafter, virtual 2-bit ACK/NACK
information is included and full bundling is performed with respect to
each of the two codewords.

[0281] Thereafter, bits of the bundled ACK/NACK information for the two
codewords may be transmitted in the form of PUCCH format 1b. If QPSK
constellation to which PUCCH format 1b is used, ACK/NACK information for
a first codeword may be mapped to a real value and ACK/NACK information
for a second codeword may be mapped to an imaginary value, without a
separate mapping table.

[0282] (3) Case in which all a plurality of detected PDCCHs includes two
codewords

[0283] First, the UE may perform spatial bundling with respect to two
codewords. Thereafter, the UE performs full bundling with respect to the
spatial-bundled ACK/NACK information. The finally bundled ACK/NACK
information bits may be transmitted in the form of PUCCH format 1a.

[0284] Meanwhile, other methods may be used. That is, the UE performs full
bundling with respect to each of the two codewords. Thereafter, the
bundled ACK/NACK information bits of the two codewords may be transmitted
in the form of PUCCH format 1b.

[0285] As described above, different bundling methods may be used
according to the number of codewords. Hereinafter, for convenience of
description, assume that spatial bundling is first performed and bundled
ACK/NACK information bits are transmitted regardless of the number of
codewords. The present invention is not limited thereto.

[0286] In order to solve the above-described problems, the present
invention provides a method of transmitting bundled ACK/NACK information
to the eNB using PUCCH resources derived from the information about the
last detected PDCCH or the information about the number of last detected
PDCCHs, which will now be described in detail.

[0287] First, DAI information is a pure counter and an assignment order of
a downlink control channel for a specific UE is represented by two bits.
This is only exemplary and DAI information may be represented using other
methods.

[0288] Next, the UE detects a PDCCH and performs full bundling using a
DAI.

[0289] At this time, in order to prevent a last PDCCH within a subframe
from being missed, bundled ACK/NACK information is reported to the eNB
using PUCCH resources derived from the information about the last PDCCH
or the information about the number of detected PDCCHs.

[0290] Here, PUCCH resources may mean physical time resources, physical
frequency resources, code resources within physical resources, or a
combination of two or more resources. Cyclic shifted codes may be used as
different resources. The above-described resources are only examples of
the PUCCH resources and the present invention is not limited thereto.

[0291] The UE calculate full-bundled ACK/NACK information and determines
PUCCH resources derived from information about the last PDCCH or the
information about the number of detected PDCCHs, calculated from
additional parameters (e.g., ARI) or calculated through RRC signaling. A
detailed method of determining PUCCH resources will be described in
detail below.

[0292] Thereafter, the UE transmits full-bundled ACK/NACK information to
the eNB using the determined PUCCH resources. That is, the UE calculates
full-bundled ACK/NACK information and transmits the calculated result
value in the form of a predetermined transmission format as final
transmission information after channel coding. Thereafter, the
full-bundled ACK/NACK information is subjected to channel coding (e.g.,
Reed-Muller coding, convolutional turbo coding, etc.) and is mapped to
the final transmission format. At this time, the final transmission
format and the channel coding scheme are not restricted by the present
invention.

[0293] Information about a last detected PDCCH, which is transmitted along
with the bundled ACK/NACK information, may be implemented as a variety of
information. For example, this information may include a total number of
detected PDCCHs, a total number of ACKs for detected PDCCHs, a total
number of missing PDCCHs, and a DAI value of a last detected PDCCH. If
transmission of ACK/NACK information of SPS is necessary based on a total
number of detected PDCCHs, a total number of ACKs for detected PDCCHs, a
total number of missing PDCCHs, and a value obtained by adding an
additional offset may be used.

[0294] In addition, a DAI value, a total number of detected PDCCHs, a
total number of ACKs for detected PDCCHs, and a total number of missing
PDCCHs may be predetermined and may be subjected to a modulo operation in
order to reduce the amount of transmitted information. In this case, the
modulo operation of Equation 3 may be applied.

[0295] Hereinafter, for convenience of description, assume that
information about a last detected PDCCH for determining PUCCH resources
used to transmit bundled ACK/NACK information is a DAI value of a last
detected PDCCH. This is only exemplary and, as described above, instead
of the DAI value, a total number of detected PDCCHs, a total number of
ACKs for detected PDCCHs or a total number of missing PDCCHs may be used.

[0296]FIG. 40 is a diagram showing an example of transmitting bundled
ACK/NACK information according to an embodiment of the present invention
via PUCCH resources determined via a DAI value of a last detected PDCCH.

[0297] In FIG. 40, assume that three component carriers are present and
each component carrier includes four subframes.

[0298] The UE indiscriminately performs full bundling with respect to a
plurality of subframes and a plurality of component carriers in a time
domain.

[0299] Referring to FIG. 40, since the UE has missed DAI information
having a value of "2", the DAI value of the last detected PDCCH becomes
"1".

[0300] The UE determines PUCCH resources used to transmit bundled ACK/NACK
information through "1" which is the DAI value of the last detected
PDCCH.

[0301] Thereafter, the UE may transmit the bundled ACK/NACK information
through the determined PUCCH resources in the form of PUCCH format 1a.

[0302] Accordingly, since the eNB can confirm the DAI value of the last
PDCCH which is successfully detected by the UE through PUCCH resources
used for ACK/NACK information transmission of the UE through the
above-described method, the received ACK/NACK information may be
accurately interpreted.

[0303] Hereinafter, an embodiment of a detailed method of determining
PUCCH resources for bundled ACK/NACK information using a DAI value of a
last detected PDCCH according to the present invention will be described.

[0304] Although it is assumed that information about a PDCCH is a DAI
value of a last detected PDCCH, this is only exemplary and a total number
of detected PDCCHs, a total number of ACKs for detected PDCCHs or a total
number of missing PDCCHs may be used instead of the DAI value.

[0305] First, according to one embodiment of the present invention, if the
DAI information of the PDCCH which was last detected by the UE is DAI
information of a primary cell, PUCCH resources for bundled ACK/NACK
information are determined using an implicit method. In addition, if the
DAI information of the PDCCH which was last detected by the UE is DAI
information of a secondary cell, PUCCH resources are determined using an
explicit method. Here, PUCCH resources determined using the explicit
method may differ according to the DAI information of the PDCCH.

[0306] The case in which the DAI information of the PDCCH which was last
detected by the UE is DAI information of a primary cell will be described
first.

[0307] At this time, a representative example of an implicit method
includes a method of using a CCE index.

[0308] More specifically, PUCCH resources used by the UE to transmit
ACK/NACK information are determined using an implicit method based on a
PDCCH carrying scheduling information of a PDSCH for transmitting
downlink data. In a downlink subframe, the entire region in which the
PDCCH is transmitted is composed of a plurality of CCEs and the PDCCH
transmitted to the UE is composed of one or more CCEs. The CCE includes a
plurality (e.g., 9) of resource element groups (REGs). One REG is
composed of four neighboring resource elements (REs) in a state of
excluding a reference signal (RS). The UE transmits ACK/NACK information
through implicit PUCCH resources derived or calculated by a function of a
specific CCE index (e.g., a first or lowest CCE index) among CCE indices
configuring the received PDCCH.

[0309] The PUCCH resource index is determined by Equation 1 below.

n.sup.(1)PUCCH=nCCE+N.sup.(1)PUCCH [Equation 1]

[0310] where, n.sup.(1)PUCCH denotes a PUCCH resource index for
transmitting ACK/NACK information and N.sup.(1)PUCCH denotes a
signal value received from a higher layer. nCCE denotes the smallest
value of CCE indices used for PDCCH transmission.

[0311] In addition, the PUCCH resource index may be determined by Table 15
and Equation 4.

[0313] In Equation 4, n.sup.(1)PUCCH,i denotes a PUCCH resource index
for transmitting ACK/NACK information, M denotes the number of elements
within the set index K defined in Table 15, i (i=0, 1, . . . , M-1)
denotes a subframe index of a PDCCH within the set index K, and p is
selected from {0, 1, 2, 3} in Np≦nCCE,i<Np+1.
Here, Np=max{0,.left
brkt-bot.[NRBDL×(NscRB×p-4)]/36.right
brkt-bot.}. NscRB denotes the size of a resource block in a
frequency domain, NRBDL denotes a downlink bandwidth
configuration, nCCE,i denotes the number of first indices used for
PDCCH transmission within the subframe, and N.sup.(1)PUCCH denotes a
signal value received from a higher layer.

[0314] That is, Equation 4 is used to stack resources and select
independent resources on a per TDD subframe basis.

[0315] The case in which DAI information of a PDCCH which was last
detected by the UE is DAI information of a secondary cell will now be
described.

[0316] At this time, a representative example of an explicit method
includes a method of using additional signaling with respect to an ACK
resource indicator (ARI).

[0317] At this time, the ARI of the secondary cell may reuse a transmit
power control (TPC) field of downlink assignment. In addition, the ARI
may directly indicate PUCCH resources or an offset for a parameter
associated with other PUCCH resources. A detailed method of using
additional signaling with respect to the ARI will now be described.

[0318] First, the ARI may represent a specific resource among a few PUCCH
resources configured from a higher layer. For example, four resources,
that is, n.sup.(1)PUCCH of Equation 1 or n.sup.(1)PUCCH,i of
Equation 4, may be configured from a higher layer. Thereafter, the ARI
may indicate which of the four PUCCH resources is actually used using 2
bits. As another example, four resources, that is, n.sup.(1)PUCCH,i
of Equation 4, may be configured according to i. Thereafter, the ARI may
indicate which of the four PUCCH resources corresponding to i is actually
used using 2 bits. Here, the index i may indicate a subframe index within
the set index k defined in Table 15 or a last detected DAI value.

[0319] The ARI may directly represent PUCCH resources. For example, the
ARI may directly indicate any one of resource indices defined in 3GPP TS
36.211. In association with this, Equation 5 or 6 is applicable.

[0320] That is, at least one n'(ns) of a plurality of n'(ns)
shown in Equation 5 or 6 may be specified (e.g., n'(0)).

[0321] As another example, PUCCH resources may be directly indicated as
shown in Table 16.

TABLE-US-00016
TABLE 16
Value of `TPC
command for PUCCH` nPUCCH.sup.(1)
`00` The first PUCCH resource index
configured by the higher layers
`01` The second PUCCH resource index
configured by the higher layers
`10` The third PUCCH resource index
configured by the higher layers
`11` The fourth PUCCH resource index
configured by the higher layers

[0322] At this time, a table for SPS may be equally reused. In addition, a
separate table and RRC signaling are configured and PUCCH resources
different from SPS may be used.

[0323] In addition, the ARI may indicate a CCE index for calculating or
deriving PUCCH resources or an offset for a CCE index of a PDCCH for
determining PUCCH resources.

[0324] In addition, the ARI may mean an offset for PUCCH resources based
on a CCE index of a PDCCH for determining PUCCH resources.

[0325] That is, the UE may determine whether DAI information of a last
detected PDCCH is for a primary cell or a secondary cell and determine
PUCCH resources using an implicit method or an explicit method according
to the determination. At this time, the eNB may confirm the DAI value of
the last PDCCH which is successfully detected by the UE using PUCCH
resources used to transmit the received ACK/NACK information and thus
accurately interpret the received ACK/NACK information.

[0326] According to another embodiment of the present invention, if DAI
information of a PDCCH which was last detected by the UE is DAI
information of a primary cell, PUCCH resources for bundled ACK/NACK
information are determined according to an implicit method. If DAI
information of a PDCCH which was last detected by the UE is DAI
information of a secondary cell, PUCCH resources corresponding to the DAI
information of the last detected PDCCH among a plurality of PUCCH
resources assigned in advance may be determined to be used.

[0327] That is, if DAI information of a PDCCH which was last detected by
the UE is DAI information of a primary cell, similarly to the
above-described embodiment, PUCCH resources for ACK/NACK information are
determined using a method of using a CCE index of the PDCCH.

[0328] If DAI information of a PDCCH which was last detected by the UE is
DAI information of a secondary cell, a plurality of PUCCH resources which
is assigned through RRC signaling in advance is used.

[0329] More specifically, the UE is assigned PUCCH resources through RRC
signaling in advance. At this time, PUCCH resources may be shared by a
plurality of UEs.

[0330] That is, PUCCH resources assigned through RRC signaling in advance
may be resources for a specific UE, resources for a specific UE group or
broadcast resources for all UEs.

[0331] At this time, the PUCCH resources assigned in advance may be
assigned regardless of serving cells set with respect to the UE and may
be differently assigned according to serving cells.

[0332] Hereinafter, a detailed method of assigning PUCCH resources to a UE
through RRC signaling in advance will be described.

[0333] First, separate PUCCH resources for DAI values (e.g., 2 bits) or
separate resources associated with PUCCH resources may be assigned
through RRC signaling. That is, different PUCCH resources mapped to DAI
values are assigned through RRC signaling in advance.

[0334] For example, if 2-bit DAI information is used, four PUCCH resources
mapped to the 2-bit DAI information in one-to-one correspondence may be
assigned to the UE through RRC signaling in advance.

[0335] In addition, separate PUCCH resources for a total number of
detected PDCCHs or separate resources associated with PUCCH resources may
be assigned through RRC signaling.

[0336] In addition, as described above, the PUCCH resources assigned in
advance may be assigned by specifying PUCCH resources or an associated
variable for calculating or deriving PUCCH resources may be assigned. For
example, resources may be assigned through an ACK resource indicator
(ARI). Hereinafter, although an associated variable for calculating or
deriving PUCCH resources is an ARI for convenience of description, the
present invention is not limited thereto.

[0337] As described above, the ARI may directly indicate PUCCH resources.
As an example thereof, at least one n'(ns) of a plurality of
n'(ns) may be specified using Equation 5 or 6 (e.g., n'(0)).

[0338] In addition, as shown in Table 16, PUCCH resources may be directly
indicated. At this time, a table for SPS may be equally reused. In
addition, a separate table and RRC signaling are configured and PUCCH
resources different from SPS may be used.

[0339] In addition, the ARI may indicate a CCE index for calculating or
deriving PUCCH resources or an offset for a CCE index of a PDCCH for
determining PUCCH resources.

[0340] In addition, the ARI may mean an offset for PUCCH resources based
on a CCE index of a PDCCH for determining PUCCH resources.

[0341] That is, the UE may determine whether DAI information of a last
detected PDCCH is for a primary cell or a secondary cell and determine
PUCCH resources using an implicit method or an explicit method according
to the method of assigning the PUCCH resources in advance. At this time,
the eNB may confirm the last DAI value which has been successfully
detected by the UE using PUCCH resources used to transmit the received
ACK/NACK information and thus accurately interpret the received ACK/NACK
information.

[0342] According to another embodiment of the present invention,
regardless of whether DAI information of a PDCCH which was last detected
by the UE is DAI information of a primary cell or a secondary cell, the
same rule may be applied to determine PUCCH resources for ACK/NACK
information.

[0343] More specifically, the UE is assigned PUCCH resources through RRC
signaling in advance. At this time, PUCCH resources may be shared by a
plurality of UEs.

[0344] That is, PUCCH resources assigned through RRC signaling in advance
may be resources for a specific UE, resources for a specific UE group or
broadcast resources for all UEs.

[0345] At this time, the PUCCH resources assigned in advance may be
assigned regardless of serving cells set with respect to the UE and may
be differently assigned according to serving cells.

[0346] Hereinafter, a detailed method of assigning PUCCH resources to a UE
through RRC signaling in advance will be described.

[0347] First, separate PUCCH resources for DAI values (e.g., 2 bits) or
separate resources associated with PUCCH resources may be assigned
through RRC signaling. That is, different PUCCH resources mapped to DAI
values are assigned through RRC signaling in advance.

[0348] For example, if 2-bit DAI information is used, four PUCCH resources
mapped to the 2-bit DAI information in one-to-one correspondence may be
assigned to the UE through RRC signaling in advance.

[0349] In addition, separate PUCCH resources for a total number of
detected PDCCHs or separate resources associated with PUCCH resources may
be assigned through RRC signaling.

[0350] In addition, as described above, the PUCCH resources assigned in
advance may be assigned by specifying PUCCH resources or an associated
variable for calculating or deriving PUCCH resources is assigned. For
example, resources may be assigned through an ACK resource indicator
(ARI). Hereinafter, although an associated variable for calculating or
deriving PUCCH resources is an ARI for convenience of description, the
present invention is not limited thereto.

[0351] As described above, the ARI may directly indicate PUCCH resources.
As an example thereof, at least one n'(ns) of a plurality of
n'(ns) may be specified using Equation 5 or 6 (e.g., n'(0)).

[0352] In addition, as shown in Table 16, PUCCH resources may be directly
indicated. At this time, a table for SPS may be equally reused. In
addition, a separate table and RRC signaling are configured and PUCCH
resources different from SPS may be used.

[0353] In addition, the ARI may indicate a CCE index for calculating or
deriving PUCCH resources or an offset for a CCE index of a PDCCH for
determining PUCCH resources.

[0354] In addition, the ARI may mean an offset for PUCCH resources based
on a CCE index of a PDCCH for determining PUCCH resources.

[0355] That is, the UE may determine PUCCH resources through RRC signaling
according to the method of assigning the PUCCH resources in advance,
regardless of whether DAI information of a last detected PDCCH is for a
primary cell or a secondary cell. At this time, the eNB may confirm the
last DAI value which is successfully detected by the UE using PUCCH
resources used to transmit the received ACK/NACK information and thus
accurately interpret the received ACK/NACK information.

[0356] Although the example of applying the present invention to a
plurality of PDCCHs included in a plurality of component carriers is
described, the present invention is not limited thereto. The present
invention is applicable to a PDCCH within at least one downlink subframe
in TDD. That is, the present invention is applicable to a method of
bundling ACK/NACK information for a PDCCH within at least one downlink
subframe including a plurality of component carriers and transmitting the
bundled ACK/NACK information to an eNB. The downlink subframe which is a
bundling unit may be referred to as a bundling window (M).

[0357] Meanwhile, the present invention may be implemented by a full
bundling method using a modified DAI.

[0358] Hereinafter, a method of setting a modified DAI value will be
described in detail.

[0359] First, a DAI value is determined in units of a predetermined
subframe. That is, the DAI values of a plurality of component carriers
located in a specific subframe are identical.

[0360] At this time, the DAI value within a specific subframe is
determined by a function from a DAI value used in a previous subframe.
That is, the DAI value is set to mean a total number of PDCCHs scheduled
in a plurality of component carriers in a specific subframe. If a
scheduled PDCCH is not present in an immediately previous first subframe,
a DAI value of a previous subframe of the first subframe is used.

[0361] In addition, an offset may be added to a DAI value of a previous
subframe, a total number of assigned PDCCHs or a calculated DAI. Even
when the DAI value is represented by the restricted bit number by adding
the offset, it is possible to prevent PDCCHs from being continuously
missed. In addition, a modulo operation may be performed with respect to
the calculated DAI value. For example, a modulo 4 operation may be
performed in order to use a 2-bit DAI value.

[0362] By using the above-described modified DAI value, the UE may confirm
a total number of PDCCHs assigned thereto within a current subframe by
comparing the DAI value of a previous subframe with the DAI value of a
current subframe. Accordingly, the UE may determine whether there is a
missing PDCCH within the subframe.

[0363] That is, if the UE successfully detects one or more PDCCHs in a
specific subframe, a determination as to whether a missing PDCCH is
present over all component carriers is made from the DAI value.

[0364] Therefore, it is possible to prevent a last PDCCH from being missed
with respect to a plurality of component carriers in advance and
accurately perform ACK/NACK bundling. In addition, like the
above-described method, it is not necessary to report the DAI value of
the last detected PDCCH to an eNB.

[0365] Since an additional report is not required, 1-bit information for
ACK or NACK is mapped to a BPSK constellation point so as to improve
performance.

[0366] In addition, unlike the conventional method, without performing
spatial bundling, each codeword may be bundled to transmit bundled
ACK/NACK information for two codewords through QPSK or channel selection.

[0367] The method of determining the modified DAI may be expressed by
Equation 7 below.

DAIi=mod {function(DAIi-1,Ni)+offset,M} [Equation 7]

[0368] where, DAIi=0, and Ni denotes the number of scheduled
PDCCHs of a plurality of component carriers located within an i-th
subframe for a specific UE. In addition, mod { } means a modulo
operation, which is used to restrict the number of bits of the DAI value.
For example, for a 2-bit DAI, M included in Equation 7 may become 4. The
setting the value of M does not restrict the present invention. For
convenience, although DAL1 is 0, the value may be an arbitrary fixed
value.

[0369] In Equation 7, an offset is used to prevent errors due to
continuous PDCCH missing. For convenience, although the offset is
described next to a function, the offset is applicable to another
variable. This is expressed by Equations 8 and 9 below.

DAIi=mod {function(DAIi-1+offset,Ni),M} [Equation 8]

DAIi=mod {function(DAIi-1,Ni+offset),M} [Equation 9]

[0370] where, the offset may be a predetermined fixed value or a
predetermined function (e.g.,
floor{function(DAIi-1,Ni+offset/DAIi}) associated with a
certain function (e.g., a subframe index, etc.) or a modulo operation
associated with a subframe. That is, the offset may be determined by at
least one of various values, equations and functions which do not require
separate signaling.

[0371] For convenience of description, assume that Equations 7 to 9 are
expressed by Equation 10 below and are applied to the present invention.

DAIi=mod {DAIi-1+Ni,4} [Equation 10]

[0372] where, DAIi denotes a DAI value transmitted on an i-th
subframe, DAL1=-1, Ni denotes the number of scheduled PDCCHs of
a plurality of component carriers located within the i-th subframe, and a
modulo 4 function is applied. Assume that the subframe index i is
sequentially increased from 0.

[0373] A detailed embodiment to which Equation 10 is applied will be
described with reference to FIGS. 41 and 42.

[0374]FIG. 41 is a diagram showing an example of using general DAI
information and modified DAI information according to an embodiment of
the present invention.

[0375] In FIG. 41, assume that the UE has missed all PDCHs for component
carriers within a second subframe of a plurality of subframes.

[0376] The DAI is a pure counter and indicates an assignment order of a
downlink control channel for a specific UE.

[0377] First, referring to FIG. 41(a), since 1 which is a last DAI of a
first subframe and 1 which is a first DAI of a third subframe are not
continuous to each other, the UE can confirm that there is a missing
PDCCH. However, a problem that it is difficult for the UE to confirm the
location of the missing PDCCH remains.

[0378] Next, referring to FIG. 41(b), a modified DAI value to which
Equation 10 is applied is applied.

[0379] That is, two scheduled PDCCHs are present in a first subframe and
the DAI value becomes mod(-1+2, 4)=1 by applying Equation 10. This value
1 is equally assigned to each of a plurality of component carriers
included in the first subframe.

[0380] Next, three scheduled PDCCHs are present in a second subframe and
the DAI value becomes mod(1+3, 4)=0 by applying Equation 10. This value 0
is equally assigned to each of a plurality of component carriers included
in the second subframe.

[0381] Next, one scheduled PDCCH is present in a third subframe and the
DAI value becomes mod(0+1, 4)=1 by applying Equation 10. This value 1 is
equally assigned to each of a plurality of component carriers included in
the third subframe.

[0382] Finally, two scheduled PDCCHs are present in a fourth subframe and
the DAI value becomes mod(1+2, 4)=3 by applying Equation 10. This value 3
is equally assigned to each of a plurality of component carriers included
in the fourth subframe.

[0383] At this time, the UE can confirm that two scheduled PDCCHs are
present in the first subframe and the set DAI value is 1. In addition,
the UE can confirm that one scheduled PDCCH is present in the third
subframe and the set DAI value is 1.

[0384] Accordingly, the UE can confirm that a missing PDCCH is present and
the missing PDCCH is present in the second subframe.

[0385] Next, FIG. 42 is a diagram showing an example of using general DAI
information and modified DAI information according to another embodiment
of the present invention.

[0386] In FIG. 42, assume that the UE has missed a PDCCH for a last
component carrier in a fourth subframe which is the last subframe of a
plurality of subframes.

[0387] Here, the DAI is a pure counter and indicates an assignment order
of a downlink control channel for a specific UE.

[0388] First, referring to FIG. 42(a), since 1 which is a last DAI of a
third subframe and 2 which is a first DAI of a fourth subframe are
continuous to each other, it is difficult for the UE to confirm that
there is a missing PDCCH.

[0389] Accordingly, in order to solve such a problem, the UE must report
information about the last detected PDCCH, that is, information about 2
which is the first DAI of the fourth subframe of FIG. 42(a), along with
bundled ACK/NACK information.

[0390] Next, referring to FIG. 42(b), a modified DAI value, to which
Equation 10 is applied, is applied. The DAI value applied to each
subframe is used equally to FIG. 40(b).

[0391] That is, since the UE knows that two scheduled PDCCHs are present
in the fourth subframe and the set DAI value is 3, the UE may recognize
that one PDCCH has been missed in the received fourth subframe.
Accordingly, since the bundled ACK/NACK information is reported to the
eNB in consideration of the above fact, additional information
transmission is not required. Therefore, it is possible to simplify the
procedure.

[0392] In addition, the DAI value is expressed by Equation 11 below and is
applicable to the present invention.

DAIi=mod {(DAIi-1+Ni)+offset,4} [Equation 11]

[0393] where, DAIi denotes a DAI value transmitted on an i-th
subframe, DAL1=-1, Ni denotes the number of scheduled PDCCHs of
a plurality of component carriers located within the i-th subframe, and a
modulo 4 function is applied. Assume that offset=1 and the subframe index
i is sequentially increased from 0.

[0394] A detailed embodiment to which Equation 11 is applicable will be
described with reference to FIG. 43.

[0395]FIG. 43 is a diagram showing an example of using general DAI
information and modified DAI information according to another embodiment
of the present invention.

[0396] In FIG. 43, assume that the UE has missed all PDCCHs for component
carriers in second and third subframes of a plurality of subframes.

[0397] Here, the DAI is a pure counter and indicates an assignment order
of a downlink control channel for a specific UE.

[0398] First, referring to FIG. 43(a), since 0 which is a last DAI of a
first subframe and 1 which is a first DAI of a fourth subframe are
continuous to each other, it is determined that a missing PDCCH is not
present. Thereafter, the erroneous result may be reported to the eNB,
causing errors.

[0399] Next, referring to FIG. 43(b), a modified DAI value, to which
Equation 10 is applied, is applied.

[0400] That is, one scheduled PDCCH is present in a first subframe and the
DAI value becomes mod(-1+1+1, 4)=1 by applying Equation 11. This value 1
is equally assigned to each of a plurality of component carriers included
in the first subframe.

[0401] Next, two scheduled PDCCHs are present in a second subframe and the
DAI value becomes mod(1+2+1, 4)=0 by applying Equation 11. This value 0
is equally assigned to each of a plurality of component carriers included
in the second subframe.

[0402] Next, two scheduled PDCCHs are present in a third subframe and the
DAI value becomes mod(0+2+1, 4)=3 by applying Equation 11. This value 3
is equally assigned to each of a plurality of component carriers included
in the third subframe.

[0403] Finally, one scheduled PDCCH is present in a fourth subframe and
the DAI value becomes mod(3+1+1, 4)=1 by applying Equation 11. This value
1 is equally assigned to each of a plurality of component carriers
included in the fourth subframe.

[0404] At this time, the UE can confirm that one scheduled PDCCH is
present in the first subframe and the set DAI value is 1. In addition,
the UE can confirm that one scheduled PDCCH is present in the fourth
subframe and the set DAI value is 1.

[0405] Accordingly, if no scheduled PDCCH is present in second and third
subframes according to the rule of Equation 11, since the value of
mode(1+1+1, 4)=3 must be set in the fourth subframe, the UE can confirm
that a missing PDCCH is present and the missing PDCCH is present in the
second and/or third subframe.

[0406] Accordingly, since the bundled ACK/NACK information is reported to
the eNB in consideration of the above fact, additional information
transmission is not required. Therefore, it is possible to simplify the
procedure.

[0407] In the present invention, if all PDCCHs of all component carriers
of the last subframe have been missed, the UE cannot confirm that all
PDCCHs have been missed.

[0408] In consideration of this case, the UE may use a method of reporting
where the last subframe detected by the UE is located using different
PUCCH resources which depend on the subframe in which the last detected
PDCCH is present.

[0409] In addition, the method of using the DAI of the present invention
(e.g., methods to which Equations 7 to 11 are applicable) is applicable
to only full bundling or both full bundling and partial bundling.

[0410] In particular, if CC-domain partial bundling is performed, the
method of using the DAI of the present invention is equally applicable to
full bundling and CC-domain bundling.

[0411] In addition, in association with the present invention, the DAI
value of the last detected PDCCH used for feedback or a total of detected
PDCCHs may include SPS feedback if necessary.

[0412] Even in the method of performing full bundling using the DAI value
described with reference to FIGS. 41 to 43, the method of assigning the
above-described PUCCH resources according to information about the PDCCH
which was last detected by the UE is applicable.

[0413] That is, the above-described method is equally applicable to PUCCH
resource assignment except for the method of using the DAI information
and the meaning thereof.

[0414] As described with reference to FIGS. 42 and 43, if the modified DAI
value is used, the problem that the last PDCCH is missed is solved by the
method of using the DAI.

[0415] That is, if a plurality of PDCCHs in the same subframe is assigned,
the UE which successfully detects one or more PDCCHs can confirm that a
missing PDCCH is present in the subframe from the DAI value.

[0416] Accordingly, if the modified DAI value is used, an element for
determining PUCCH resources is changed. That is, if such a DAI is used,
the PUCCH derived from the last detected PDCCCH or a total number of
PDCCHs is not used but the PUCCH derived from the last subframe in which
one or more PDCCH is detected, a total number of detected PDCCHs or a
total number of subframes in which the detected PDCCH is present may be
used.

[0417] Hereinafter, for convenience of description, assume that
information for determining PUCCH resources used to transmit bundled
ACK/NACK information is a last subframe in which at least one PDCCH is
detected.

[0418] However, this is only exemplary and, as described above, a total
number of detected PDCCHs or a total number of subframes in which the
detected PDCCH is present may be used instead of the last subframe in
which one or more PDCCHs are detected.

[0419] First, according to one embodiment of the present invention, if
information about a last subframe in which one or more PDCCHs are
detected is information about a primary cell, the UE determines PUCCH
resources for bundled ACK/NACK information according to an implicit
method.

[0420] In addition, if information about a last subframe in which one or
more PDCCHs are detected is information about a secondary cell, the UE
determines PUCCH resources according to an explicit method.

[0421] The case in which information about a last subframe in which one or
more PDCCHs are detected is information about a primary cell will first
be described.

[0422] At this time, a representative example of an implicit method
includes a method of using a CCE index of a PDCCH.

[0423] That is, as described above, the UE may transmit ACK/NACK
information through implicit PUCCH resources derived or calculated from a
function a specific CCE index (e.g., a first or lowest CCE index) among
CCE indices configuring the received PDCCH.

[0424] The indices of the PUCCH resources may be determined by Equations 1
and 4.

[0425] Meanwhile, the case in which information about a last subframe in
which one or more PDCCHs are detected is information about a secondary
cell will be described.

[0426] At this time, a representative example of an explicit method
includes a method of using additional signaling with respect to an ACK
resource indicator (ARI).

[0427] At this time, the ARI of the secondary cell may reuse a transmit
power control (TPC) field of downlink assignment. In addition, the ARI
may directly indicate PUCCH resources or an offset for a parameter
associated with other PUCCH resources. A detailed method of using
additional signaling with respect to the ARI may be implemented by
directly indicating any one of resource indices defined using Equations 5
and 6 as described above. In addition, as shown in Table 16, PUCCH
resources may be directly indicated. At this time, a table for SPS may be
equally reused.

[0428] In addition, a separate table and RRC signaling are configured and
PUCCH resources different from SPS may be used.

[0429] In addition, the ARI may indicate a CCE index for calculating or
deriving PUCCH resources or an offset for a CCE index of a PDCCH for
determining PUCCH resources.

[0430] In addition, the ARI may mean an offset for PUCCH resources based
on a CCE index of a PDCCH for determining PUCCH resources.

[0431] That is, the UE may determine whether information about a last
subframe in which one or more PDCCHs are detected is information about a
primary cell or a secondary cell and determine PUCCH resources using an
implicit method or an explicit method according to the determination. At
this time, the eNB may confirm information about the last subframe which
is successfully detected by the UE using PUCCH resources used to transmit
the received ACK/NACK information and thus accurately interpret the
received ACK/NACK information.

[0432] According to another embodiment of the present invention, if
information about a last subframe in which one or more PDCCHs are
detected is information about a primary cell, the UE determines PUCCH
resources for bundled ACK/NACK information according to an implicit
method. If information about a last subframe in which one or more PDCCHs
are detected is information about a secondary cell, the UE determines use
of PUCCH resources corresponding to the information about the last
detected subframe of the plurality of PUCCH resources assigned in advance
through RRC signaling.

[0433] That is, if information about a last subframe in which one or more
PDCCHs are detected is DAI information of a primary cell, PUCCH resources
for ACK/NACK information are determined through a method of using a CCE
index of a PDCCH, similarly to the above-described embodiment.

[0434] However, if information about a last subframe in which one or more
PDCCHs are detected is DAI information of a secondary cell, a plurality
of PUCCH resources assigned through RRC signaling in advance is used.

[0435] More specifically, the UE is assigned PUCCH resources through RRC
signaling. At this time, PUCCH resources may be shared by a plurality of
UEs.

[0436] That is, PUCCH resources assigned through RRC signaling in advance
may be resources for a specific UE, resources for a specific UE group or
broadcast resources for all UEs.

[0437] At this time, the PUCCH resources assigned in advance may be
assigned regardless of serving cells set with respect to the UE and may
be differently assigned according to serving cells.

[0438] Hereinafter, a detailed method of assigning PUCCH resources to a UE
through RRC signaling in advance will be described.

[0439] First, separate PUCCH resources for the last detected subframe
information or separate resources associated with PUCCH resources may be
assigned through RRC signaling. That is, different PUCCH resources mapped
to the last detected subframe information are assigned through RRC
signaling in advance.

[0440] For example, if 2-bit last detected subframe information is used,
four PUCCH resources mapped to the 2-bit last detected subframe
information in one-to-one correspondence may be assigned to the UE
through RRC signaling in advance.

[0441] In addition, separate PUCCH resources for a total number of
detected PDCCHs or separate resources associated with PUCCH resources may
be assigned through RRC signaling.

[0442] In addition, as described above, the PUCCH resources assigned in
advance may be assigned by specifying PUCCH resources or an associated
variable for calculating or deriving PUCCH resources may be assigned. For
example, resources may be assigned through an ACK resource indicator
(ARI). Hereinafter, although an associated variable for calculating or
deriving PUCCH resources is an ARI for convenience of description, the
present invention is not limited thereto.

[0443] As described above, the ARI may directly indicate PUCCH resources.
As an example thereof, at least one n'(ns) of a plurality of
n'(ns) may be specified using Equation 5 or 6 (e.g., n'(0)).

[0444] In addition, as shown in Table 16, PUCCH resources may be directly
indicated. At this time, a table for SPS may be equally reused. In
addition, a separate table and RRC signaling are configured and PUCCH
resources different from SPS may be used.

[0445] In addition, the ARI may indicate a CCE index for calculating or
deriving PUCCH resources or an offset for a CCE index of a PDCCH for
determining PUCCH resources.

[0446] In addition, the ARI may mean an offset for PUCCH resources based
on a CCE index of a PDCCH for determining PUCCH resources.

[0447] That is, the UE may determine whether DAI information of last
detected subframe information is for a primary cell or a secondary cell
and determine PUCCH resources using an implicit method or an explicit
method or through RRC signaling according to the method of assigning the
PUCCH resources in advance. At this time, the eNB may confirm the last
subframe information which is successfully detected by the UE using PUCCH
resources used to transmit the received ACK/NACK information and thus
accurately interpret the received ACK/NACK information.

[0448] According to another embodiment of the present invention,
regardless of whether the subframe information which was last detected by
the UE is for a primary cell or a secondary cell, the same rule may be
applied to determine PUCCH resources for ACK/NACK information.

[0449] More specifically, the UE is assigned PUCCH resources through RRC
signaling in advance. At this time, PUCCH resources may be shared by a
plurality of UEs.

[0450] That is, PUCCH resources assigned through RRC signaling in advance
may be resources for a specific UE, resources for a specific UE group or
broadcast resources for all UEs.

[0451] At this time, the previously assigned PUCCH resources may be
assigned regardless of serving cells set with respect to the UE and may
be differently assigned according to serving cells.

[0452] Hereinafter, a detailed method of assigning PUCCH resources to a UE
through RRC signaling in advance will be described.

[0453] First, separate PUCCH resources for last subframe information
(e.g., 2 bits) or separate resources associated with PUCCH resources may
be assigned through RRC signaling. That is, different PUCCH resources
mapped to the last detected subframe information are assigned through RRC
signaling in advance.

[0454] For example, if 2-bit last detected subframe information is used,
four PUCCH resources mapped to the 2-bit subframe information in
one-to-one correspondence may be assigned to the UE through RRC signaling
in advance.

[0455] In addition, separate PUCCH resources for a total number of
detected PDCCHs or separate resources associated with PUCCH resources may
be assigned through RRC signaling.

[0456] In addition, as described above, the PUCCH resources assigned in
advance may be assigned by specifying PUCCH resources or an associated
variable for calculating or deriving PUCCH resources is assigned. For
example, resources may be assigned through an ACK resource indicator
(ARI). Hereinafter, although an associated variable for calculating or
deriving PUCCH resources is an ARI for convenience of description, the
present invention is not limited thereto.

[0457] As described above, the ARI may directly indicate PUCCH resources.
As an example thereof, at least one n'(ns) of a plurality of
n'(ns) may be specified using Equation 5 or 6 (e.g., n'(0)).

[0458] In addition, as shown in Table 16, PUCCH resources may be directly
indicated. At this time, a table for SPS may be equally reused. In
addition, a separate table and RRC signaling are configured and PUCCH
resources different from SPS may be used.

[0459] In addition, the ARI may indicate a CCE index for calculating or
deriving PUCCH resources or an offset for a CCE index of a PDCCH for
determining PUCCH resources.

[0460] In addition, the ARI may mean an offset for PUCCH resources based
on a CCE index of a PDCCH for determining PUCCH resources.

[0461] That is, the UE may determine whether the last detected subframe
information is for a primary cell or a secondary cell and determine PUCCH
resources through RRC signaling according to the method of assigning the
PUCCH resources in advance. At this time, the eNB may confirm the last
subframe information which is successfully detected by the UE using PUCCH
resources used to transmit the received ACK/NACK information and thus
accurately interpret the received ACK/NACK information.

[0462] Although a plurality of PDCCHs included in a plurality of component
carriers is described in the above description, the present invention is
not limited thereto. The present invention is applicable to a PDCCH
within at least one downlink subframe in TDD. That is, the present
invention is applicable to a method of bundling ACK/NACK information for
a PDCCH within at least one downlink subframe including a plurality of
component carriers and transmitting the bundled ACK/NACK information to
an eNB. The downlink subframe which is a bundling unit may be referred to
as a bundling window (M).

[0463] The present invention is applicable by instructing the UE through a
higher layer configuration or according to a specific state of the UE.

[0464] The above-described embodiment are applied for transmission of a
variety of uplink control information and the same principle may be
applied to make the number of pieces of SR information and ACK/NACK
information various. In addition, a plurality of embodiments may be
combined to obtain another control information transmission method. In
addition, the transmission bit of the embodiment is applicable to control
information transmission of various embodiments.

[0465] The aforementioned embodiments are achieved by combination of
structural elements and features of the present invention in a
predetermined manner. Each of the structural elements or features should
be considered selectively unless specified separately. Each of the
structural elements or features may be carried out without being combined
with other structural elements or features. Also, some structural
elements and/or features may be combined with one another to constitute
the embodiments of the present invention. The order of operations
described in the embodiments of the present invention may be changed.
Some structural elements or features of one embodiment may be included in
another embodiment, or may be replaced with corresponding structural
elements or features of another embodiment. Moreover, it will be apparent
that some claims referring to specific claims may be combined with other
claims referring to the other claims other than the specific claims to
constitute the embodiment or add new claims by means of amendment after
the application is filed.

[0466] The above-mentioned embodiments of the present invention are
disclosed on the basis of a data communication relationship between a
base station and a terminal Such a communication relationship is
equally/similarly extended to signal communication between a terminal and
a relay or a base station and a relay. Specific operations to be
conducted by the base station in the present invention may also be
conducted by an upper node of the base station as necessary. In other
words, it will be obvious to those skilled in the art that various
operations for enabling the base station to communicate with the user
equipment in a network composed of several network nodes including the
base station will be conducted by the base station or other network nodes
other than the base station. The term "Base Station" may be replaced with
a fixed station, Node-B, eNode-B (eNB), or an access point as necessary.
The term "terminal" may also be replaced with a user equipment (UE), a
mobile station (MS), a mobile subscriber station (MSS) or a mobile
terminal as necessary.

[0467] The embodiments of the present invention can be implemented by a
variety of means, for example, hardware, firmware, software, or a
combination of them. In the case of implementing the present invention by
hardware, the present invention can be implemented with application
specific integrated circuits (ASICs), Digital signal processors (DSPs),
digital signal processing devices (DSPDs), programmable logic devices
(PLDs), field programmable gate arrays (FPGAs), a processor, a
controller, a microcontroller, a microprocessor, etc.

[0468] If operations or functions of the present invention are implemented
by firmware or software, the present invention can be implemented in the
form of a variety of formats, for example, modules, procedures,
functions, etc. The software codes may be stored in a memory unit so that
it can be driven by a processor. The memory unit is located inside or
outside of the processor, so that it can communicate with the
aforementioned processor via a variety of well-known parts.

[0469] The detailed description of the exemplary embodiments of the
present invention has been given to enable those skilled in the art to
implement and practice the invention. Although the invention has been
described with reference to the exemplary embodiments, those skilled in
the art will appreciate that various modifications and variations can be
made in the present invention without departing from the spirit or scope
of the invention described in the appended claims. For example, those
skilled in the art may use each construction described in the above
embodiments in combination with each other. Accordingly, the invention
should not be limited to the specific embodiments described herein, but
should be accorded the broadest scope consistent with the principles and
novel features disclosed herein.

INDUSTRIAL APPLICABILITY

[0470] Although a method and device for transmitting control information
in a wireless communication system is applied to a 3GPP LTE system, this
is applicable to a various wireless communication systems in addition to
the 3GPP LTE system.